\nComprehensive Python language reference. Cheatsheet speed!\n\nThis is an interactive Python language reference. Covers the core Python programming language. Find answers instantly by using 'find'.\n\n\nSpeedsheet Repo: https://github.com/speedsheet/sheet-python\n\n\n
Speedsheet Help Tips\n\nCheck out our tips page for pro-level tricks to get the most out of this cheat sheet.
\n\n\nBeautiful is better than ugly.\nExplicit is better than implicit.\nSimple is better than complex.\nComplex is better than complicated.\nFlat is better than nested.\nSparse is better than dense.\nReadability counts.\nSpecial cases aren't special enough to break the rules.\nAlthough practicality beats purity.\nErrors should never pass silently.\nUnless explicitly silenced.\nIn the face of ambiguity, refuse the temptation to guess.\nThere should be one-- and preferably only one --obvious way to do it.\nAlthough that way may not be obvious at first unless you're Dutch.\nNow is better than never.\nAlthough never is often better than *right* now.\nIf the implementation is hard to explain, it's a bad idea.\nIf the implementation is easy to explain, it may be a good idea.\nNamespaces are one honking great idea -- let's do more of those!\n\n\n\n"},{"id":"gXDF","level":1,"heading":"Hello World","content":"
\n\nCreate and run the following Python script.\n\n\nFile Name:\n\n
hello.py
\n\nFile Contents:\n\n
print("Hello World!")
\n\nRun From The Command-line:\n\n
python3 hello.py
\n\n\n\n"},{"id":"wUPN","level":2,"heading":"Hello World - With Input","content":"
Hello World - With Input
\n\nFile Name:\n\n
hello2.py
\n\nFile Contents:\n\n
def main():\n\n\tname = input("Enter Name: ")\n\n\tif not name:\n\t\tname = "World"\n\n\tprint("hello " + name + "!")\n\n\nif __name__ == "__main__":\n\tmain()
\n\nRun From The Command-line:\n\n
python3 hello2.py
\n\n\n\n"},{"id":"bW8t","level":2,"heading":"Hello World - With Command-line Arguments","content":"
Hello World - With Command-line Arguments
\n\nThis version takes one argument and displays it as the name.\n\n\nFile Name:\n\n
hello2.py
\n\nFile Contents:\n\n
from sys import argv\t\t#1\n\ndef main():\n\n\tif len(argv) > 1:\t\t\t#2\n\t\tname = argv[1]\t\t\t#3\n\telse:\n\t\tname = "World"\t\t\t#4\n\n\tprint("hello " + name + "!")\n\n\nif __name__ == "__main__":\n\tmain()
\n\nRun From The Command-line:\n\n
python3 hello2.py your_name_here
\n\n\n#1 - Importing argv allows the program to get arguments passed in from the command-line.\n\n#2 - Check if any arguments were passed in.\n\n#3 - Take the first argument as the name.\n\n#4 - The default value for the name when none is given.\n\n\n\n"},{"id":"4pcY","level":1,"heading":"Language Fundamentals","content":"
\n\nGuido van Rossum\n\n\n\n"},{"id":"wr4h","level":2,"heading":"Comments","content":"
Comments
\n\n
# This is a comment.
\n\nStart the comment with a hash '#'.\nComments are ignored by the compiler.\n\n\n\n"},{"id":"qaRb","level":2,"heading":"Comments - Multiline","content":"
Comments - Multiline
\n\nThere are no multiline comments in Python.\n\n\n\n"},{"id":"dkqF","level":2,"heading":"DocString","content":"
DocString
\n\n
"""Python Docstring."""
\n\nThey are defined as a text between a set of 3 double quotes.\nPlace after the class or function definition.\n\nSee also: __doc__\n\n\nExamples:\n\n
def documented_function():\n\t"""This docstring\n\tdocuments the function of this function\n\t"""
\n\nBlocks are defined by indentation.\n\nCode on the same indent level are in the same block.\nPython will not allow mixed indentation\n\n\nExample:\n\n
\n\nCase sensitive.\nThe first character must be an alphabet letter or underscore, not a digit.\nAll other characters can be alphabet letters, underscores or digits.\n\n\nExamples:\n\n
\n\nPath to modules and packages.\n\n\nPython checks PYTHONPATH directories for modules and packages.\nPython adds this to sys.path.\n\n\n\n"},{"id":"cbGR","level":2,"heading":"Passing Arguments - Pass By Assignment (Default)","content":"
Passing Arguments - Pass By Assignment (Default)
\n\nPass by Assignment\n\nPython passes by assignment by default (same as pass by value).\nObjects are passed by assigning the object reference.\n\n\n\n"},{"id":"ySrE","level":2,"heading":"Passing Arguments - Options","content":"
Passing Arguments - Options
\n\nCall Passing as list:\n\n
= func_1(*list_1)\t\t\t#1
\n\nCall Passing as dict:\n\n
= func_2(**dict_1)\t\t\t#2
\n\n\nReceive as list:\n\n
def func_3(*args):\t\t\t#3\n\t...
\n\nReceive as dict:\n\n
def func_4(**kwargs):\t\t#4\n\t...
\n\n\n#1 -list_1 will be unpacked to function arguments in list order.\n\n#2 -dict_1 will be converted into their named arguments inside the function.\n\n#3 - Converts arguments to a list.\n\n#4 - Converts named arguments to a dict.\n\n\n\n"},{"id":"XQEY","level":2,"heading":"Scope","content":"
Scope
\n\nScope Levels\n\n\tModule\n\tClass\n\tFunction\n\tClosure\n\tGenerator Expression\n\tComprehension\n\nThere is no block level scope\n\n\nExample:\n\n
\n\n\nPython calls this as the starting module by default.\n\n\n\n"},{"id":"yDmw","level":2,"heading":"Statement - Multiline Statement","content":"
Statement - Multiline Statement
\n\n
... \\\n...
\n\nThe '\\' at the line's end indicates line continues on next line.\n\n\nNote:\n\nPrefer using parenthesis '( )', brackets '[ ]', braces '{ }' for multiline statements for clarity.\n\n\nExample:\n\n
string_1 = "Part 1 and " + \\\n\t\t"part 2 and " + \\\n\t\t"part 3"
\n\n\n"},{"id":"3uus","level":3,"heading":"Convention - Class Names","content":"
Convention - Class Names
\n\n
class ClassName1:
\n\nUse TitleCase, no underscore separator.\n\n\n\n"},{"id":"Nr5q","level":3,"heading":"Convention - Function Names","content":"
Convention - Function Names
\n\n
def function_name_1...
\n\nUse snake case, all lower case letters, underscores between words.\n\n\n\n"},{"id":"KkGY","level":3,"heading":"Convention - Magic Methods","content":"
Convention - Magic Methods
\n\n
__magic_method_name__
\n\nLead and end with a double underscore. All letters are lower case. Words are separated by underscores.\n\n\n\n"},{"id":"7fYT","level":3,"heading":"Convention - Module Names","content":"
Convention - Module Names
\n\n
short_name
\n\nUse a short name for module file names. Use snake case if necessary.\n\n\n\n"},{"id":"ju3Q","level":3,"heading":"Convention - Private Names","content":"
Convention - Private Names
\n\n
_private_name_1
\n\nIdentify variables and functions as private by leading with an underscore.\n\n\nExamples:\n\n
\n\nUse upper snake case, all upper case letters, underscore separator between words.\n\nNote: There is no mechanism in Python to enforce constants. They are normal variables.\n\n\nExample:\n\n
\n\nShows the current python version from the command-line.\n\n\n\n"},{"id":"QJeY","level":2,"heading":"REPL - Start","content":"
REPL - Start
\n\n
python3
\n\n\nStarts the REPL.\n\n\n\n"},{"id":"YUM9","level":2,"heading":"REPL - Get Last Evaluated Expression","content":"
REPL - Get Last Evaluated Expression
\n\n
= _
\n\n
print (_)
\n\nUnderscore '_' stores the result of the last evaluated expression.\n\n\n\n"},{"id":"NYz9","level":2,"heading":"REPL - Exit","content":"
REPL - Exit
\n\n
Control + D
\n\n
exit()
\n\n\nPress the keys Control + D or type exit() to quit.\n\n\n\n"},{"id":"5wcE","level":2,"heading":"Application / Script - Run Program","content":"
Application / Script - Run Program
\n\n
python3 python_file.py
\n\nRun from the source root directory.\n\n\n\n"},{"id":"VkJW","level":2,"heading":"Application / Script - Run Module","content":"
Application / Script - Run Module
\n\n
python3 -m package.module_name
\n\nRun from parent directory to the package directory.\npackage is the directory containing the module.\nmodule_name is the python module file without the .py extension.\n\nRun from source root directory.\n\n\n\n"},{"id":"WxnY","level":2,"heading":"Application - Run Directory","content":"
Application - Run Directory
\n\n
python3 source_directory
\n\nThis will run a python program from it's source directory.\n\nThe source directory must contain __main__.py.\nPlace your startup code in that file.\nPython will call it to start the application.\n\n\nDirectory Structure:\n\n
src/\n\t__main__.py\n\t...
\n\nRun:\n\n
python3 src
\n\n\n\n"},{"id":"gfQR","level":1,"heading":"Unit Test - Command-line","content":"
Unit Test - Command-line
\n\n\n\n"},{"id":"xa1J","level":2,"heading":"Unit Test - Run All","content":"
Unit Test - Run All
\n\n
python3 -m unittest
\n\nPython will search for and run all tests in the current directory and subdirectories.\n\n\n\n"},{"id":"TMUa","level":2,"heading":"Unit Test - Run Module","content":"
Unit Test - Run Module
\n\n
python3 -m unittest module_name
\n\n
python3 -m unittest package_name.module_name
\n\nRun from source root directory.\n\n\n\n"},{"id":"qSvH","level":2,"heading":"Unit Test - Run Test Class","content":"
\n\nRun from source root directory.\n\n\n\n"},{"id":"A9p5","level":1,"heading":"Distribution","content":"
Distribution
\n\n\n\n"},{"id":"kt3Z","level":2,"heading":"Application Distribution - Egg - Create","content":"
Application Distribution - Egg - Create
\n\nSteps:\n\n
Create the startup module __main__.py.
\n
Zip all python files into a single zip file.
\n\n\nZip the contents of the source folder into a zip file to create a distibutable egg file.\nInclude the __main__.py file. This will be called on startup of the egg file.\n\nThe root directory of the zip file must be the root directory of the python source files.\nDo not place files into a directory in the zip file.\n\n\n\n"},{"id":"1KdM","level":2,"heading":"Application Distribution - Egg - Run","content":"
Application Distribution - Egg - Run
\n\n
python3 egg_file.egg
\n\n
python3 egg_file.zip
\n\n\nThis will run an egg file by calling the included __main__.py file.\n\nInstall and run an environment prior to running the egg file, if required.\n\n\n\n"},{"id":"d8xz","level":2,"heading":"Application Distribution - Egg - Starting Module","content":"
Application Distribution - Egg - Starting Module
\n\n
__main__.py
\n\n\nAdd a module called __main__.py to your code.\nPython will call this when starting your application.\n\n\n\n"},{"id":"Th7c","level":2,"heading":"Application Distribution - Wheel - Setup","content":"
Application Distribution - Wheel - Setup
\n\nSteps:\n\n
Create setup.py
\n
Create /src/__init_-.py
\n\n\nCreate setup.py in the project directory.\nCreate __init__.py in the source root directory.\n\n\nExample setup.py:\n\n
\n\n\n\n"},{"id":"zgWJ","level":2,"heading":"Application Distribution - Wheel - Create","content":"
Application Distribution - Wheel - Create
\n\n
python3 setup.py sdist bdist_wheel
\n\nRun from project root directory.\nCreates wheel distribution file in the/dist.\n\n\n\n"},{"id":"aTYy","level":1,"heading":"PIP - Package Manager","content":"
PIP - Package Manager
\nPython's Package Manager.\n\nInstalls and manages libraries and their dependencies.\n\nPIP = PIP Installs Packages\n\n\n\n"},{"id":"UmeF","level":2,"heading":"PIP - Installed Package Location","content":"
PIP - Installed Package Location
\n\n
python_home_directory/lib/python3.x/site-packages
\n\nThe location of packages installed by PIP.\n\n\n\n"},{"id":"R58v","level":2,"heading":"PIP - Requirements File","content":"
\n\nPlace in project root directory.\n\n\nNote: The requrements.txt name is by convention only.\n\n\n\n"},{"id":"TmHH","level":3,"heading":"PIP - Requirements File - Sample File","content":"
PIP - Requirements File - Sample File
\n\nIn requirements.txt:\n\n
# This is a comment line.\n\npackage_1_name\t\t\t\t\t# Latest Version\n\npackage_2==1.2.3\t\t\t\t# Specific Version\n\npackage_3>=1.2.3\t\t\t\t# Specific Version or Higher\n\n-r other_requirements.txt\t\t# Include packages from this file too.
\n\n\n\n"},{"id":"2XZL","level":3,"heading":"PIP - Package - Install From Requirements File","content":"
PIP - Package - Install From Requirements File
\n\n
pip install -r requirements.txt
\n\nInstalls all the packages listed in the requirements.txt file.\n\n\n\n"},{"id":"Bujb","level":3,"heading":"PIP - Package - Install From Wheel File","content":"
PIP - Package - Install From Wheel File
\n\n
pip install package_name.whl
\n\n\n\n"},{"id":"edn2","level":3,"heading":"PIP - Package - Install Using Proxy","content":"
\n\n\n\n"},{"id":"R3xL","level":3,"heading":"PIP - Packages - List All","content":"
PIP - Packages - List All
\n\n
pip list
\n\nLists all installed packages and their versions.\n\n\n\n"},{"id":"q9Qw","level":3,"heading":"PIP - Packages - Upgrade All","content":"
PIP - Packages - Upgrade All
\n\n
pip install -r requirements.txt
\n\n\nUpgrades any existing libraries.\n\nJust run normal install command to upgrade the libraries.\n\n\n\n"},{"id":"MZ4e","level":3,"heading":"PIP - Requirements File - Create","content":"
PIP - Requirements File - Create
\n\n
pip freeze > requirements.txt
\n\nCreate requirements file from installed packages.\n\nUses the packages installed in the current virtual environment.\nIf no environment, uses the global packages.\n\n\n\n"},{"id":"VbdZ","level":1,"heading":"Operators","content":"
\n\n\nPerforms a bitwise complement on the value.\nBecause Python's integers are signed, this is not a straight inversion of the bits.\n\n\nExample:\n\n
a = 0b110\n\ncomplement = ~a\n\nprint(f'{complement:b}')\n\n# Prints: -111
\n\n\nis and is not compare items' identities to see if they are the same.\nid compares memory locations.\n\n\n\n"},{"id":"pvjS","level":2,"heading":"Operators - Is Empty?","content":"
Operators - Is Empty?
\n\n
= not var_1
\n\n
if not var_1:\n\t...
\n\nUse on sequences, strings, lists, sets, dicts, tuples.\n\n\nExample:\n\n
if not dict_1:\n\tprint("dict_1 is empty.")\nelse:\n\tprint("dict_1 not empty.")
\n\n\n\n"},{"id":"wW10","level":2,"heading":"Operators - Not Empty?","content":"
Operators - Not Empty?
\n\n
if var_1:\n\t...
\n\nUse on sequences, strings, lists, sets, dicts, tuples.\n\n\nExample:\n\n
if dict_1:\n\tprint("dict_1 not empty.")\nelse:\n\tprint("dict_1 is empty.")
\n\n\n\n"},{"id":"nKzP","level":2,"heading":"Operators - Is Between","content":"
Operators - Is Between
\n\n
= min < value < max\n\n= min <= value <= max
\n\n
if min < value < max:\n\t...\n\nif min <= value <= max:\n\t...
\n\n\nExamples:\n\n
value = 1\n\n# True:\n\nprint (0 < value < 2)\n\n`alse:\n\nprint (1 < value < 2)\n\n# True:\n\nprint (1 <= value < 2)
if condition_1:\n\t...\nelif condition_2:\n\t...\nelse:\n\t...
\n
\n
\n
For
for i in range(max_plus_1):\n\t...
\n
\n
\n
for item in sequence_1:\n\t...
\n
\n
\n
for item in sequence_1:\n\t...\n\tbreak\n\t...\n\tcontinue\nelse:\n\t...
\n
\n
\n
Match
match variable_1:\n\n case value_1:\n ...\n\n case value_2 | value_3:\n ...\n\n case (value_4_1, value_4_2):\n ...\n\n case Class1(param_1, param_2):\n ...\n\n case Enum1.ENUM_1:\n ...\n\n case (value_8, x):\n ...\n\n case (value_8, x) if condition:\n ... \n\n case _:\n ...
\n
\n
\n
While
while condition:\n\t...
\n
\n
\n
while condition:\n\t...\n\tbreak\n\t...\n\tcontinue\n\t...\nelse:\n\t...
match expression:\n\n case value_1:\n ...\n\n case value_2 | value_3:\t\t\tMatches Either Value\n ...\n\n case (value_4_1, value_4_2):\tTuple\n ...\n\n case [value_5_1, value_5_2]:\tList\n ...\n\n case {key_6: value_6}:\t\t\tDict (Contains)\n ...\n\n case Class1(field_1, field_2):\tClass\n ...\n\n case Enum1.ENUM_1:\t\t\t\tEnum\n ...\n\n case (value_8, x):\t\t\t\tBind To Variable\n ...\n\n case (value_8, x) if condition:\n ... \n\n case _:\t\t\t\t\t\t\tUnmatched\n ...
\n\n\n\n"},{"id":"w1fh","level":3,"heading":"Match - Bind To Variable","content":"
Match - Bind To Variable
\n\n
match expression:\n case variable_1:\n ...\n case (value, variable_1):\n ...\n case (variable_1, variable_2, variable_3):\n ...\n case _:\n ...
\n\n\nCaptures one or more values and binds them to variables.\n\n\nExample:\n\n
item_1 = (1, 2)\n\nmatch item_1:\n case (1, a):\n print (f'(1, a = {a})')\n case (2, b):\n print (f'(2, b = {b})')\n case _:\n print('Unmatched Value')\n\n# Prints: (1, a = 2)
\n\n\n\n"},{"id":"H9yk","level":3,"heading":"Match - Match Specific Values","content":"
Match - Match Specific Values
\n\n
match expression:\n case value_1:\n ...\n case value_2 | value_3:\n ...\n case _:\n ...
\n\n\nMatches the value of the variable with the value of the case statements.\nIf matched, the case statement will execute.\n\n\nExamples:\n\n
int_1 = 2\n\nmatch int_1:\n case 1:\n print ('Value 1')\n case 2 | 3:\n print ('Value 2 or 3')\n case _:\n print ('Unmatched Value')\n\n# Prints: 'Value 2 or 3'
\n\n\n
month = 'feb'\n\nmatch int_1:\n case 'jan':\n print ('January')\n case 'feb':\n print ('February')\n case _:\n print ('Unmatched Month')\n\n# Prints: 'It's February'
\n\n\n\n"},{"id":"pmxN","level":3,"heading":"Match - Match 'Constants'","content":"
Match - Match 'Constants'
\n\n
class Constants:\n CONSTANT_1 = value_1\n CONSTANT_2 = value_2\n\nmatch value_1:\n case Constants.CONSTANT_1:\n ...\n case Constants.CONSTANT_2:\n ...\n case _:\n ...
\n\n\nDefine constants in a class and reference them statically.\n\nNote: If you do not include the class name, match will think these are structural pattern variables and will assign values to them.\n\n\n
class Status:\n\tOK = 'ok'\n\tERROR = 'error'\n\nstatus = 'ok'\n\nmatch status:\n case Status.OK:\n print ("Status OK")\n case Status.ERROR:\n print ("Status Error")\n case _:\n print ("Status Unknown")\n\n# Prints: "Status OK"
\n\n\n\n"},{"id":"1MYF","level":3,"heading":"Match - Match Classes","content":"
Match - Match Classes
\n\n
match value:\n case Class1():\n ...\n case Class2(field_1, field_2:\n ...\n case _:\n ...
\n\n\nMatches on class type and class field values.\n\n\n\n"},{"id":"UAfp","level":3,"heading":"Match - Match Dict","content":"
Match - Match Dict
\n\n
match dict_1:\n case {key_1: value_1}:\n ...\n case {key_2: value_2, key_3: value_3}:\n ...\n case _:\n ...
\n\n\nMatches key, value pairs in a dictionary.\nIf the pair exists, the case block will execute.\nThis is independent of any other values in the dict.\n\n\nExamples:\n\n
dict_1 = {'b': 'b1', 'z': 'z1'}\n\nmatch dict_1:\n case {'a': 'a1'}:\n print('Value a:a1')\n case {'b': 'b0'}:\n print('Value b:b0')\n case {'b': 'b1'}:\n print('Value b:b1')\n case _:\n print('Unmatched value.')\n\n# Prints: 'Value b:b1'
\n\n\n\n"},{"id":"f0jB","level":3,"heading":"Match - Match Enums","content":"
Match - Match Enums
\n\n
class Enum1(Enum):\n ENUM_1 = value_1\n ENUM_2 = value_2\n\nmatch value_1:\n case Enum1.ENUM_1:\n ...\n case Enum1.ENUM_2:\n ...\n case _:\n ...
\n\n\nMatches the values of an enumerated type.\n\n\n
from enum import Enum, auto\n\nclass Status(Enum):\n OK = 'ok'\n ERROR = 'error'\n\nstatus = Status.OK\n\nmatch status:\n case Status.OK:\n print ("Status OK")\n case Status.ERROR:\n print ("Status Error")\n case _:\n print ("Status Unknown")\n\n# Prints: "Status OK"
\n\n\n\n"},{"id":"G65u","level":3,"heading":"Match - Match Lists","content":"
Match - Match Lists
\n\n
match list_1:\n case [value_1]:\n ...\n case [value_2]:\n ...\n case [value_3_1, value_3_2]:\n ...\n case _:\n ...
\n\n\nMatches the internal values of the variable with the value of the case statements.\nIf matched, the case statement will execute.\n\n\nExample:\n\n
list_1 =[1, 3]\n\nmatch list_1:\n case [1]:\n print ('Value [1]')\n case [1, 2]:\n print ('Value [1, 2]')\n case [1, 3]:\n print ('Value [1, 3]')\n case _:\n print ('Unmatched Value')\n\n# Prints: Value (1, 3)'
\n\n\n\n"},{"id":"77v3","level":3,"heading":"Match - Match Tuples","content":"
Match - Match Tuples
\n\n
match tuple_1:\n case (value_1):\n ...\n case (value_2):\n ...\n case (value_3_1, value_3_2):\n ...\n case _:\n ...
\n\n\nMatches the internal values of the variable with the value of the case statements.\nIf matched, the case statement will execute.\n\n\nExample:\n\n
tuple_1 =(1, 3)\n\nmatch tuple_1:\n case (1):\n print ('Value (1)')\n case (1, 2):\n print ('Value (1, 2)')\n case (1, 3):\n print ('Value (1, 3)')\n case _:\n print ('Unmatched Value')\n\n# Prints: Value (1, 3)'
\n\n\n\n"},{"id":"yTZB","level":3,"heading":"Match - Match If / Conditionally","content":"
Match - Match If / Conditionally
\n\n
match item_1:\n case ... if condition:\n ...
\n\n\nWill match the case only when condition is met.\n\n\nExamples:\n\n
value = 2\n\nmatch value:\n case x if x % 2 == 0:\n print(f'Value {value} is even.')\n case x if x % 2 == 1:\n print(f'Value {x} is odd.')\n case _:\n print('Unmatched value')\n\nPrints: 'Value 2 is even.'
\n\n
item_1 = (1, 2)\n\nmatch item_1:\n case (1, x) if x % 2 == 0:\n print('Value (1,x) x is even.')\n case (1, x):\n print('Value (1,x) x is odd.')\n case _:\n print('Unmatched value')\n\nPrints: 'Value (1,x) x is even.'
\n\n\n\n"},{"id":"GDqy","level":3,"heading":"Match - Fall Through","content":"
Match - Fall Through
\n\nNot Supported.\n\nUnlike other languages, match does not fall through from one case block into the next. There is no need for a break statement within a case block to exit the block.\n\n\n\n"},{"id":"teQD","level":3,"heading":"Match - Unmatched / Wildcard","content":"
Match - Unmatched / Wildcard
\n\n
match item_1:\n\n case _:\n ...
\n\n\n_ catches all values that were not matched in any other case statements.\n\n\n
item_1 = -1\n\nmatch item_1:\n case 1:\n print('Value 1')\n case 2:\n print('Value 2')\n case _:\n print('Unmatched Value')\n\nPrints: 'Unmatched Value'
while condition:\n\t...\nelse:\n\t...# When condition = False
\n\n
while condition:\n\t...\n\tbreak # Exit for loop.\n\t...\n\tcontinue # Jump to next iteration.\n\t...\nelse:\n\t...# When condition = False
\n\nelse block reached when condition = false only. Not called for break, exception, etc.\n\n\n\n"},{"id":"v8H0","level":3,"heading":"While","content":"
While
\n\n
while condition:\n\t...
\n\n\n\n"},{"id":"32w5","level":3,"heading":"While - While Else","content":"
While - While Else
\n\n
while condition:\n\t...\nelse:\n\t...
\n\nExecutes else clause when condition is False.\n\nbreak skips the else block. \n\n\n\n"},{"id":"6syd","level":3,"heading":"While - Break Continue","content":"
While - Break Continue
\n
while condition:\n\t...\n\tbreak # Exit for loop.\n\t...\n\tcontinue # Jump to next iteration.\n\t...
\n\n\nbreak will skip the else block if one is included.\n\n\n\n"},{"id":"ZkWp","level":2,"heading":"While - \"Do-While\" Form","content":"
While - "Do-While" Form
\n\n
while True:\n\n\t...\n\n\tif exit_condition:\n\t\tbreak
\n\n\nExecutes the while loop at least one time.\n\n\n\n"},{"id":"60TY","level":2,"heading":"Break","content":"
Break
\n\nExit Loop:\n\n
break
\n\nApplies to for and while loops.\n\nbreak will skip the else block if one is included.\n\n\n\n"},{"id":"afz9","level":2,"heading":"Continue","content":"
Continue
\n\nContinue on Next Iteration:\n\n
continue
\n\nApplies to for and while loops.\n\n\n\n"},{"id":"DNLt","level":2,"heading":"Pass","content":"
Pass
\n\n
pass
\n\nUse as a placeholder in places where a code block should exist but you don't have any code yet.\n\n\nExamples:\n\n
\n\n\nCreates a new variable called name with value value.\n\n\nExamples:\n\n
int_1 = 11
\n\n
float_1 = 9.75
\n\n
string_1 = 1Life, the universe, and everything1
\n\n\n\n"},{"id":"WcH5","level":2,"heading":"Variable - Global - Create or Update","content":"
Variable - Global - Create or Update
\n\n
global name
\n\n\nUpdates an existing global variable from inside a function.\nWithout the keyword global, Python will create a local variable.\n\nCreates a new global variabel if it doesn't exist.\n\n\nUsage:\n\n
def some_function():\n\n\tglobal name\n\tname = value
\n\n\nExample:\n\n
global_1 = 'Global Value'\n\n\ndef update_global():\n\n\tglobal global_1\n\tglobal_1 = global_1 + ' + Update'\n\n\nupdate_global()\n\n# Sets global_1 to 'Global Value + Update'
\n\nWithout the keyword nonlocal, Python will create a local variable.\nThe non-local variable must be in scope of the nested function declaration.\nWorks with multi-level nesting.\nYou can not create a non-existing variable.\n\n\nNote:\n\nThe function already has read access to the parent variables through closure.\nConsider avoiding updating the values.\n\n\nExample:\n\n
def parent_function:\n\n\tcount = 0\n\n\tdef update_count():\n\n\t\tnonlocal count\n\t\tcount += 1\n\n\tupdate_count()\n\n\t# count is now 1
\n\n\tdict\t\t\t(Dictionary of Key Value Pairs)\n\tset\t\t\t\t(Mutable Set)\n\tfrozenset\t\t(Immutable Set)\n\n\n\n"},{"id":"sMQY","level":2,"heading":"Mutable Types","content":"
\n\n\tboolean\n\tbyte\n\tfloat\n\tfrozenset\n\tint\n\tlong\n\tcomplex\n\tstr\n\ttuple\n\n\n\n"},{"id":"T5aC","level":1,"heading":"Data Types - From Library","content":"
Data Types - From Library
\n\n\n\n"},{"id":"hEdW","level":2,"heading":"Date And Time","content":"
Date And Time
\n\n\tdate\t\t\t\t(Date Only)\n\tdatetime\t\t\t(Date And Time)\n\ttimedelta\t\t\t(Time Difference)\n\n\tfloat (timestamp)\t\t(Epoch Time, Seconds Since 1970) (Use float)\n\n\n\n"},{"id":"E7zG","level":2,"heading":"Collections","content":"
Collections
\n\n\tchainmap\n\tcounter\n\tdeque\n\tdefaultdict\n\tnamedtuple\n\tordereddict\n\tuserdict\n\tuserlist\n\tuserstring\n\n\tarray\t\t\t(List Constrained To A Single Basic Type)\n\n\n\n"},{"id":"NnXJ","level":2,"heading":"Enumerations","content":"
\n\nEscapes an _ value into a string character.\n\nWatch for any trailing digit characters that are not part of the octal value. They will be incorporated.\n\n\nEquivalent:\n\n
from decimal import getcontext\n\n= getcontext().rounding
\n\n\nGets the rounding performed on decimal operations (*, /, etc.).\nThe default rounding is ROUND_HALF_EVEN.\n\n\n\n"},{"id":"bvw4","level":2,"heading":"Decimal - Rounding - Set","content":"
Decimal - Rounding - Set
\n\n
from decimal import getcontext\n\ngetcontext().rounding = rounding
\n\n\nSets the rounding performed on decimal operations (*, /, etc.).\nThe default rounding is ROUND_HALF_EVEN.\n\n\nRounding Values:\n\n
decimal.ROUND_CEILING
Round Up To + Infinity
0.5 -> 1\n-0.5 -> 0\n
\n
decimal.ROUND_DOWN
Round To 0
0.5 -> 0\n-0.5 -> 0\n
\n
decimal.ROUND_FLOOR
Round Down To - Infinitiy
0.5 -> 0\n-0.5 -> -1\n
\n
decimal.ROUND_HALF_DOWN
Round To Nearest Integer\nTies Round to 0
0.6 -> 1\n 0.5 -> 0\n-0.5 -> 0\n-0.6 -> -1\n
\n
decimal.ROUND_HALF_EVEN
Round To Nearest Integer\nTies To Nearest Even Integer
\n\n
\n
decimal.ROUND_HALF_UP
Round To Nearest Integer\nTies Round to
0.5 -> 2\n 0.4 -> 0\n-0.4 -> 0\n-0.5 -> 2\n
\n
decimal.ROUND_UP
Round To ± Infinity
0.5 -> 1\n-0.5 -> -1\n
\n
decimal.ROUND_05UP
Round To 0\nExcept When Last Rounded Digit = 0 or 5\n- Then Round To ± Infinity
from decimal import getcontext\n\n= getcontext().prec
\n\n\nGets the precision for decimal operations (*, /, etc.).\nThe default precision is 28 digits including digits before and after the decimal place.\n\n\n\n"},{"id":"1aX0","level":2,"heading":"Decimal - Precision - Set","content":"
Decimal - Precision - Set
\n\n
from decimal import getcontext\n\ngetcontext().prec = digits
\n\n\nSets the precision for decimal operations (*, /, etc.).\nThe default precision is 28 digits including digits before and after the decimal place.\n\n\nExample:\n\n
from decimal import Decimal\nfrom decimal import getcontext\n\na = Decimal('1')\nb = Decimal('0.3')\n\nprint(a / b)\n\n# Prints 3.333333333333333333333333333\n\ngetcontext().prec = 4\n\nprint(a / b)\n\n# Prints 3.333
\n\nType: float\n\n\nImmutable.\nUnderscores between digits are ignored. Use them to make numbers more readable.\n\n\n\n"},{"id":"fqtK","level":2,"heading":"Decimal - To Float","content":"
Decimal - To Float
\n\n
= float(decimal_1)
\n\nConverts a decimal to a float.\n\n\n\n"},{"id":"GfMN","level":2,"heading":"Decimal - To Integer","content":"
Decimal - To Integer
\n\n
= int(decimal_1)
\n\nConverts a decimal to a int.\n\n\n\n"},{"id":"b25U","level":1,"heading":"Float Operations","content":"
\n\nType: int\n\n\nImmutable.\nLength 32 or 64 bits. Depends on the machine.\nUnderscores between numbers are ignored. Use them to make the number more readable.\n\n\n\n"},{"id":"u0H4","level":1,"heading":"Integer Operations","content":"
Integer Operations
\n\n\n\n"},{"id":"CPVx","level":2,"heading":"Integer - Is Zero","content":"
Integer - Is Zero
\n\n
= not int_1
\n\n
if not int_1:\n\t...
\n\n\n\n"},{"id":"nbRK","level":2,"heading":"Integer - Not Zero","content":"
\n\n\n\n"},{"id":"kHyR","level":2,"heading":"Integer - Maximum Value","content":"
Integer - Maximum Value
\n\n
import sys\n\nmax_size = sys.maxsize
\n\nThe maximum value of an integer is system dependent.\nUse this function to find the value in your current environment.\n\n\n32 bits = 2,147,483,647\n64 bits = 9,223,372,036,854,775,807\n\n\n\n"},{"id":"GQSJ","level":1,"heading":"String","content":"
String
\n\n
= "A String"\n= 'A String'\n= str(34) # Returns '34'
\n\n\nReturns text exactly as it is represented between the quotes.\n\nNo escaped character processing is done.\nUseful for regular expressions.\n\n\nExample:\n\n
normal_string = 'a\\tb\\tc'\nraw_string = r'a\\tb\\tc'\n\nprint("Normal", normal_string)\nprint("Raw ", raw_string)\n\n# Prints:\n#\n# Normal a b c\n# Raw a\\tb\\tc
\n\n\n\n"},{"id":"N7SB","level":1,"heading":"String Format - Format()","content":"
\n\n\n\n"},{"id":"dYcf","level":1,"heading":"String Format - F-String","content":"
String Format - F-String
\n\n\nFormatted String literal or f-string.\n\nCreates a formatted string using a string literal.\n\n\n\n"},{"id":"Nqj2","level":2,"heading":"F-String - Basics","content":"
F-String - Basics
\n\n
Variable
= f'{var_1}'
'value-1'
\n
= f"{var_1}"
'value-1'
\n
\n
Text and Variable
= f'text {var_1}'
'text value-1'
\n
= f"text {var_1}"
'text value-1'
\n
\n
Concatenate
= f'{string_1}{string_2}'
'value-1value-2'
\n
= f'{string_1}' f'{string_2}'
'value-1value-2'
\n
\n
Align Right
= f'{string_1:>10}'
' value-1'
\n
Align Center
= f'{string_1:^10}'
' value-1 '
\n
Align Left
= f'{string_1:<10}'
'value-1 '
\n
\n
Comma
= f'{float_1:,}'
'12,345'
\n
Decimals
= f'{float_1:.2f}'
'12345.12'
\n
Comma, Decimals
= f'{float_1:,.2f}'
'12,345.12'
\n\n\n\n"},{"id":"7Qze","level":2,"heading":"F-String - Single Variable","content":"
F-String - Single Variable
\n\n
= f'{item_1}'\n\n= f"{item_1}"
\n\n\nExample:\n\n
string_1 = "norminal"\n\nformatted = f"Everything is {string_1}."\n\n# Returns "Everything is norminal."
\n\nAppends string_2 to the end of string_1.\n\n\n\n"},{"id":"sWmR","level":2,"heading":"String - Concatenate","content":"
String - Concatenate
\n\n
= string_1 + string_2 + ...
\n\nConcatenate Raw Strings:\n\n
= "String 1" "String 2" ...
\n\nCombines 2 or more strings into one string.\n\n\n"},{"id":"zQRH","level":2,"heading":"String - Contains?","content":"
String - Contains?
\n\n
= string_1 in string_2
\n\n
if string_1 in string_2:\n\t...
\n\nReturns True when string_1 is a substring of string_2.\n\n\n\n"},{"id":"rckU","level":2,"heading":"String - Not Contains?","content":"
String - Not Contains?
\n\n
= string_1 not in string_2
\n\n
if string_1 not in string_2:\n\t...
\n\nReturns True when string_1 is not a substring of string_2.\n\n\n\n"},{"id":"X5wj","level":2,"heading":"String - Ends With?","content":"
String - Ends With?
\n\n
= string_1.endswith(test_value)
\n\nReturns: bool\n\n\nReturns True if string_1 ends with or equals test_value.\n\n\n\n"},{"id":"r3vd","level":2,"heading":"String - Find","content":"
String - Find
\n\n
= string_1.find(search_value)
\n\n
= string_1.find(search_value, start)
\n\n
= string_1.find(search_value, start, end)
\n\nReturns: integer\n\nIf -1 is returned then no match was found.\n\n\n\n"},{"id":"wYvE","level":2,"heading":"String - Find Last","content":"
String - Find Last
\n\n
= string_1.rfind(search_value)
\n\nReturns: integer\n\nIf -1 is returned then no match was found.\n\n\n\n"},{"id":"bqeq","level":2,"heading":"String - Get Character","content":"
String - Get Character
\n\n
= string_1[position]
\n\nExample:\n\n
character_2 = "012345"[2]\n\n# Returns "2"
\n\n\n\n"},{"id":"D4hp","level":2,"heading":"String - Is Blank?","content":"
String - Is Blank?
\n\n
= not string_1 or string_1.isspace()
\n\n
if not string_1 or string_1.isspace():\n\t...
\n\n\nReturns True for None or "" or is all whitespace.\n\n\n\n"},{"id":"UGSs","level":2,"heading":"String - Is Empty?","content":"
String - Is Empty?
\n\n
= not string_1
\n\n
if not string_1:\n\t...
\n\n\nReturns True for None or "".\n\n\n\n"},{"id":"nqSR","level":2,"heading":"String - Not Empty?","content":"
String - Not Empty?
\n\n
= (string_1 != None and string_1 != "")
\n\n
if string_1 != None and string_1 != "":\n\t...
\n\n\nReturns False for None or "".\n\n\nA bit messy.\nThere isn't a clean Pythonic way to do this.\nI recommend making a function like this:\n\n
def not_empty(value):\n\treturn value != None and value != ""
\n\nThen call like this:\n\n
if not_empty(string_1):\n\t...
\n\n\n\n"},{"id":"rwYB","level":2,"heading":"String - Is Equal?","content":"
String - Is Equal?
\n\n
= string_1 == string_2
\n\n
if string_1 == string_2:\n\t...
\n\n\nExample:\n\n
if "a" == "b":\n\tprint("Equal")\nelse:\n\tprint("Not Equal")
\n\n\n\n"},{"id":"9TXm","level":2,"heading":"String - Not Equal?","content":"
String - Not Equal?
\n\n
= string_1 != string_2
\n\n
if string_1 != string_2:\n\t...
\n\n\nExample:\n\n
if "a" != "b":\n\tprint("Not Equal")\nelse:\n\tprint("Equal")
\n\n\n\n"},{"id":"6TEG","level":2,"heading":"String - Is Equal, Ignore Case?","content":"
String - Is Equal, Ignore Case?
\n\n
= string_1.casefold() == string_2.casefold()
\n\n
if string_1.casefold() == string_2.casefold():\n\t...
\n\n\ncasefold() is the correct way to compare strings caselessly.\nThis is especially true for unicode strings.\ncasefold() convents the string to a safe case agnostic form.\n\n\nExample:\n\n
if "stoß".casefold() == "STOSS".casefold():\n\tprint("Equal")\nelse:\n\tprint("Not Equal")\n\n# These Are Equal
\n\n\n\n"},{"id":"b3tQ","level":2,"heading":"String - Not Equal, Ignore Case?","content":"
String - Not Equal, Ignore Case?
\n\n
= string_1.casefold() != string_2.casefold()
\n\n
if string_1.casefold() != string_2.casefold():\n\t...
\n\n\ncasefold() is the correct way to compare strings caselessly.\nThis is especially true for unicode strings.\ncasefold() convents the string to a safe case agnostic form.\n\nExample:\n\n
if "stoß".casefold() != "STOSS".casefold():\n\tprint("Not Equal")\nelse:\n\tprint("Equal")\n\n# These Are Equal
\n\n\n\n"},{"id":"Aqbs","level":2,"heading":"String - is Alpha Only","content":"
String - is Alpha Only
\n\n
= string_1.isalpha()
\n\nReturns True if consisting entirely of alphabet characters.\n\nIncludes international characters.\nReturns False for numbers, symbols, emojis, or whitespace characters.\n\n\n\n"},{"id":"LTAf","level":2,"heading":"String - is Alphanumerics Only","content":"
String - is Alphanumerics Only
\n\n
= string_1.isalnum()
\n\nReturns True if consisting entirely of alphabet characters or numbers..\n\nIncludes international characters.\nReturns False for symbols, emojis, or whitespace characters.\n\n\n\n"},{"id":"afRz","level":2,"heading":"String - Is Digits Only","content":"
String - Is Digits Only
\n\n
= string_1.isdigit()
\n\n\nChecks if a string consists of digits only.\n\n\nReturns True when all characters are from 0 to 9.\nReturns False for + or -\n\n\n\n"},{"id":"v1NL","level":2,"heading":"String - Is Integer","content":"
String - Is Integer
\n\n
from re import match\n\ndef is_int(value):\n\treturn match(r"^[+-]?\\d+$", value) is not None
\n\n
= is_int(string_1)
\n\n\nWorks for any integer including those with plus or minus.\n\n\n\n"},{"id":"j97W","level":2,"heading":"String - Is Lower Case Only","content":"
String - Is Lower Case Only
\n\n
= string_1.islower()
\n\n\nChecks if a string consists of all lower case letters.\n\n\n\n"},{"id":"h9Wh","level":2,"heading":"String - Is Title Case Only","content":"
String - Is Title Case Only
\n\n
= string_1.istitle()
\n\n\nChecks if a string consists of all title case words.\n\nTo be True every word must start with a capitalized letter and the remaining letters must be lower case.\n\n\n\n"},{"id":"k1aP","level":2,"heading":"String - Is Upper Case Only","content":"
String - Is Upper Case Only
\n\n
= string_1.isupper()
\n\n\nChecks if a string consists of all upper case letters.\n\n\n\n"},{"id":"9aB2","level":2,"heading":"String - Is Valid Python Identifier","content":"
String - Is Valid Python Identifier
\n\n
= string_1.isidentifier()
\n\n\nChecks if a string is a valid Python identifier.\n\nChecks to see that the string meets the identifier name rules (starts with [a-zA-Z_] followed by [a-zA-Z0-9_])\n\n\n\n"},{"id":"2S3c","level":2,"heading":"String - Iterate Over Characters","content":"
String - Iterate Over Characters
\n\n
for character in string_1:\n\t...
\n\nIterates over string_1 one character at a time.\n\n\n\n"},{"id":"LfuC","level":2,"heading":"String - Compare?","content":"
String - Compare?
\n\nIs Less Than?:\n\n
= string_1 < string_2
\n\nIs Greater Than?:\n\n
= string_1 > string_2
\n\n\nCompare strings using ==, !=, <, >, <=, >=.\n\n\nExample:\n\n
if "a" < "b":\n\tprint("Less Than")\nelse:\n\tprint("Not Less Than")
\n\n\n\n"},{"id":"EedD","level":2,"heading":"String - Pad on Left","content":"
String - Pad on Left
\n\n
= string_1.rjust(width) # Pad With Spaces
\n\n
= string_1.rjust(width, fill_char)
\n\nPads string_1 on the left side to the given width.\nPads with fill_char, or spaces if not given.\n\n\n\n"},{"id":"eS9g","level":2,"heading":"String - Pad on Right","content":"
String - Pad on Right
\n\n
= string_1.ljust(width) # Pad With Spaces
\n\n
= string_1.ljust(width, fill_char)
\n\nPads string_1 to the given width on the right side.\nPads with fill_char, or spaces if not given.\n\n\n\n"},{"id":"NV7z","level":2,"heading":"String - Repeat","content":"
\n\n\nReplaces all occurrenceses of a substring with another.\n\nReplace is case sensitive.\n\n\nExample:\n\n
string_1 = 'Replace this and this and this.'\nreplaced = string_1.replace('this', 'that')\n\nprint(replaced)\n\n# Prints 'Replace that and that and that.'
\n\n\n\n"},{"id":"h5uK","level":2,"heading":"String - Replace First Occurence","content":"
String - Replace First Occurence
\n\n
= string_1.replace(original, replacement, 1)
\n\n\nReplaces the first occurrencese of a substring with another.\n\nReplace is case sensitive.\n\n\nExample:\n\n
string_1 = 'Replace this and this and this.'\nreplaced = string_1.replace('this', 'that', 1)\n\nprint(replaced)\n\n# Prints 'Replace that and this and this.'
\n\n\nReplaces the occurrences of one string with another\n\nReplace is not case sensitive.\n\n\nExample:\n\n
import re\n\nstring_1 = 'Replace this and THIS and ThIs.'\n\npattern = re.compile('this', re.IGNORECASE)\nreplaced = pattern.sub('that', string_1)\n\nprint(replaced)\n\n# Prints 'Replace that and this and this.'
\n\n\n\n"},{"id":"e79V","level":2,"heading":"String - Replace Ignore Case, First Occurrence","content":"
\n\n\nReplaces the occurrences of one string with another\n\nReplace is not case sensitive.\n\n\nExample:\n\n
import re\n\nstring_1 = 'Replace this and THIS and ThIs.'\n\npattern = re.compile('this', re.IGNORECASE)\nreplaced = pattern.sub('that', string_1, 1)\n\nprint(replaced)\n\n# Prints 'Replace that and this and this.'
\n\nReturns a list of strings split on split_string.\n\nsplit_string is not returned in the results.\nStops after splitting split_count times if given.\n\n\nExamples:\n\n
\n\n\n\n"},{"id":"gHcV","level":2,"heading":"String - Split From End","content":"
String - Split From End
\n\n
= string_1.rsplit(split_string)
\n\n
= string_1.rsplit(split_string, split_count)
\n\nReturns a list of strings split on split_string starting from the end.\nsplit_string is not returned in the results.\nStops after splitting split_count times if given.\n\n\nExample:\n\n
\n\n\nReturns: tuple\n\n\nSplits the string into 3 parts: before partition, partition and after partition.\nIf the partition can't be found, returns the string followed by two empty strings.\nSplits at the first match only.\n\n\nExamples:\n\n
\n\nReturns: bool\n\n\nReturns True if string_1 begins with or equals test_value.\n\n\n\n"},{"id":"yk5k","level":2,"heading":"String - Strip","content":"
String - Strip
\n\n
= string_1.strip()
\n\nRemoves all whitespace characters from the beginning and end of the string.\n\n\n\n"},{"id":"dpZ5","level":2,"heading":"String - Strip Left","content":"
String - Strip Left
\n\n
= string_1.lstrip()
\n\nRemoves all whitespace characters at the start of the string.\n\n\n\n"},{"id":"C3S7","level":2,"heading":"String - Strip Right","content":"
String - Strip Right
\n\n
= string_1.rstrip()
\n\nRemoves all whitespace characters at the end of the string.\n\n\n\n"},{"id":"3gfd","level":2,"heading":"String - Substitute / Translate - With Dict","content":"
\n\nReturns: str\n\n\nFinds characters from originals in string_1 and replaces them with the matching characters from replacements.\n\noriginals and replacements must be the same size.\n\n\nExample:\n\n
originals = '123'\nreplacements = 'ABC'\ntranslation = str.maketrans(originals, replacements)\n\nstring_1 = 'Items 1, 2, 3'\ntranslated = string_1.translate(translation)\n\n# Returns: 'Items A, B, C'
\n\n\nUse this when you need to compare two strings but ignore the case (caseless).\n\nConverts the string into a safe case agnostic form.\nThis is very important for unicode characters.\n\nWhy?\nBecause case rules (uppercase, lowercase) can get complicated, especially in foreign languages.\nSome languages have more than one case or special rules for when a particular form of letter should be used.\n\n\nExample:\n\n
\n\n\nReplaces one or more of the date units with a new value.\n\n\nUnit Ranges:\n\n
Year
1 - 9999
\n
Month
1 - 12
\n
Day
1 - Last-Day-Of-Month
\n\n\nExample:\n\n
from datetime import date\n\ntoday = date.today()\n\nstart_of_month = today.replace(day = 1)\n\nprint("Start of Month:", start_of_month)
\n\n\n\n"},{"id":"rhbw","level":2,"heading":"Date - To Year","content":"
Date - To Year
\n\n
= date_1.year
\n\n\n\n"},{"id":"N7A1","level":2,"heading":"Date - To Month","content":"
Date - To Month
\n\n
= date_1.month
\n\n\n\n"},{"id":"876U","level":2,"heading":"Date - To Day","content":"
Date - To Day
\n\n
= date_1.day
\n\n\n\n"},{"id":"9RM3","level":2,"heading":"Date - To Day of Week","content":"
Date - To Day of Week
\n\n
= date_1.weekday()
\n\n\nReturns: int\n\nThat is .weekday() with a ().\n\n0 is Monday.\n6 is Sunday.\n\n\n\n"},{"id":"RctT","level":2,"heading":"Date - From Timestamp","content":"
Date - From Timestamp
\n\n
from datetime import date\n\ndate_1 = date.fromtimestamp(timestamp_1)
\n\n\n\n"},{"id":"VVKu","level":2,"heading":"Date - From String","content":"
Date - From String
\n\n
from datetime import datetime\n\ndate_1 = datetime.strptime(date_string, date_format).date()
\n\n\nYou must convert to a datetime first, then to a date.\n\n\nExamples:\n\n
\n\n\nConverts a date into a string.\n\nA typical format would be '%Y-%m-%d' or '%m/%d/%Y'.\n\n\nExample:\n\n
from datetime import date\n\ndate_1 = date(2001, 1, 1)\n\n# These are equivalent:\n\nstring_1 = f'{date_1:%Y-%m-%d}'\nstring_2 = '{:%Y-%m-%d}'.format(date_1)\nstring_3 = date_1.isoformat()\nstring_4 = date_1.strftime('%Y-%m-%d')\n\n# Returns '2001-01-01'
\n\n\n\n"},{"id":"A850","level":2,"heading":"Date - From ISO-8601 String","content":"
Date - From ISO-8601 String
\n\n
from datetime import date\n\ndate_1 = date.fromisoformat(iso_date_string)
\n\n\nAccepted Format:\n\n
'YYYY-MM-DD'
\n\n\nExample:\n\n
from datetime import date\n\ndate_1 = date.fromisoformat("2000-01-02")
\n\n
from datetime import date\nfrom datetime import datetime\n\n# These are equivalent:\n\ndate_1 = date.fromisoformat("2000-01-02")\ndate_2 = datetime.strptime("2000-01-02", "%Y-%m-%d").date()
\n\n\n\n"},{"id":"VUH5","level":2,"heading":"Date - To ISO-8601 String","content":"
from datetime import date\n\ndate_1 = date.today()\n\n# These are equivalent:\n\nstring_1 = date_1.isoformat()\nstring_2 = date_1.strftime('%Y-%m-%d')\nstring_3 = ':%Y-%m-%d'.format(date_1)
\n\n\n\n"},{"id":"jfDG","level":2,"heading":"Datetime - Create UTC Time (Deprecated)","content":"
Datetime - Create UTC Time (Deprecated)
\n\nThis is deprecated and will be removed from future Python releases\n\n
= datetime.utcnow()
\n\nUsage:\n\n
from datetime import datetime\n\n= datetime.utcnow()
\n\n\nUse this instead:\n\n
= datetime.now(tz = timezone.utc)
\n\n\nReturns the current UTC time.\n\n\nDoes not include time zone information.\n\n\n\n"},{"id":"FYEQ","level":2,"heading":"Datetime - Create Now","content":"
Datetime - Create Now
\n\n
= datetime.now()
\n\nUsage:\n\n
from datetime import datetime\n\n= datetime.now()
\n\nReturns: datetime\n\n\nReturns an instance of the current date time.\n\n\nExample:\n\n
from datetime import datetime\n\ndate_1 = datetime.now()
\n\n\n\n"},{"id":"kuxZ","level":2,"heading":"Datetime - now() vs today()","content":"
Datetime - now() vs today()
\n\nnow():\n\n
Preferred
\n
Allows for Time Zone
\n\ntoday()\n\n
No Time Zone Allowed
\n\n\nPrefer now() to today().\n\nnow() allows for time zone information to be included.\nBut in reality for non time zone datetimes, they are equivalent.\n\n\n\n"},{"id":"fK6t","level":1,"heading":"DateTime - Operations","content":"
\n\n\nReplaces one or more of the datetime units with a new value.\n\n\nUnit Ranges:\n\n
Year
1 - 9999
\n
Month
1 - 12
\n
Day
1 - Last-Day-Of-Month
\n
Hour
0 - 23
\n
Minute
0 - 59
\n
Second
0 - 59
\n
Microseconds
0 - 999,999
\n\n\nExample:\n\n
from datetime import datetime\n\nnow = datetime.now()\n\nstart_of_day = now.replace(\n hour = 0,\n minute = 0,\n second = 0,\n microsecond = 0)\n\nprint("Start of Day:", start_of_day)
\n\n\n\n"},{"id":"a7GE","level":2,"heading":"DateTime - To Year","content":"
DateTime - To Year
\n\n
= datetime_1.year
\n\n\n\n"},{"id":"4hza","level":2,"heading":"DateTime - To Month","content":"
DateTime - To Month
\n\n
= datetime_1.month
\n\n\n\n"},{"id":"D1T2","level":2,"heading":"DateTime - To Day","content":"
DateTime - To Day
\n\n
= datetime_1.day
\n\n\n\n"},{"id":"Pr4c","level":2,"heading":"DateTime - To Day of Week","content":"
DateTime - To Day of Week
\n\n
= datetime_1.weekday()
\n\n\nReturns: int\n\nYes, this is .weekday() with a ().\n\n0 is Monday.\n6 is Sunday.\n\n\n\n"},{"id":"XRXf","level":2,"heading":"DateTime - To Hour","content":"
DateTime - To Hour
\n\n
= datetime_1.hour
\n\n\n\n"},{"id":"krUt","level":2,"heading":"DateTime - To Minute","content":"
DateTime - To Minute
\n\n
= datetime_1.minute
\n\n\n\n"},{"id":"dcud","level":2,"heading":"DateTime - To Second","content":"
DateTime - To Second
\n\n
= datetime_1.second
\n\n\n\n"},{"id":"WhhG","level":2,"heading":"DateTime - To Date","content":"
DateTime - To Date
\n\n
= datetime_1.date()
\n\n\n\n"},{"id":"ZKhj","level":2,"heading":"DateTime - To Time","content":"
DateTime - To Time
\n\n
= datetime_1.time()
\n\n\n\n"},{"id":"qupG","level":2,"heading":"DateTime - From Timestamp","content":"
DateTime - From Timestamp
\n\n
from datetime import datetime\n\ndatetime_1 = datetime.fromtimestamp(timestamp_1)
\n\n\nGet the datetime for the given timestamp or epoch time (the number of seconds since 1969-12-31 19:00:00).\n\n\n\nExample:\n\n
from datetime import datetime\n\n# These are equivalent:\n\ndate_1 = datetime.fromisoformat("2020-11-30 23:59:59")\ndate_2 = datetime.strptime("2020-11-30 23:59:59", '%Y-%m-%d %H:%M:%S')
\n\n\n\n"},{"id":"0qN7","level":2,"heading":"DateTime - To String","content":"
\n\n\n\n"},{"id":"55xw","level":2,"heading":"DateTime - From ISO-8601 String","content":"
DateTime - From ISO-8601 String
\n\n
from datetime import datetime\n\ndatetime_1 = datetime.fromisoformat(iso_date_time_string)
\n\n\nAccepted Formats:\n\n
'YYYY-MM-DDhh:mm:ss'\n'YYYY-MM-DDThh:mm:ss'
\n\n\nExample:\n\n
from datetime import datetime\n\ndate_1 = datetime.fromisoformat("2020-11-30 23:59:59")
\n\n
from datetime import datetime\n\n# These are equivalent:\n\ndate_1 = datetime.fromisoformat("2020-11-30 23:59:59")\ndate_2 = datetime.strptime("2020-11-30 23:59:59", '%Y-%m-%d %H:%M:%S')
\n\n\n\n"},{"id":"Q8gY","level":2,"heading":"DateTime - To ISO-8601 String","content":"
\n\n\n\n"},{"id":"WULc","level":2,"heading":"TimeDelta - Get Microseconds","content":"
TimeDelta - Get Microseconds
\n\n
= timedelta_1.microseconds
\n\n\nReturns: int\n\n\n"},{"id":"WYmg","level":2,"heading":"TimeDelta - Get Milliseconds","content":"
TimeDelta - Get Milliseconds
\n\n
= timedelta_1.microseconds // 1000
\n\nReturns: int\n\n\nThere is no built in way to do this.\nDivide .microseconds by 1000 instead.\n\n\n\n"},{"id":"p7HX","level":2,"heading":"TimeDelta - Get Seconds","content":"
TimeDelta - Get Seconds
\n\n
= timedelta_1.seconds
\n\n\nReturns: int\n\n\nReturns the number of seconds for the portion less than a day.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"ucNH","level":2,"heading":"TimeDelta - Get Total Seconds","content":"
TimeDelta - Get Total Seconds
\n\n
= timedelta_1.total_seconds()
\n\n\nReturns: float\n\n\nReturns the timedelta in seconds.\nReturns fraction of a second too.\n\n\n\n"},{"id":"LRC8","level":2,"heading":"TimeDelta - Is Equal?","content":"
\n\n\nReturns: float\n\n\nReturns the number of seconds in Unix Time or Epoch Time.\nMeasures from the Epoch, January 1, 1970, at 00:00:00 UTC.\n\n\nExample:\n\n
Set to 2001-01-01 00:00:00:\n\ntimestamp_1 = 978325200.0
\n\n\n\n"},{"id":"desF","level":2,"heading":"Timestamp - From Datetime","content":"
Timestamp - From Datetime
\n\n
= datetime_1.timestamp()
\n\n\n\n"},{"id":"47cQ","level":2,"heading":"Timestamp - To Datetime","content":"
Timestamp - To Datetime
\n\n
= datetime.fromtimestamp(timestamp_1)
\n\nUsage:\n\n
from datetime import datetime\n\n= datetime.fromtimestamp(timestamp_1)
\n\n\n\n"},{"id":"Tpzg","level":2,"heading":"Timestamp - To String","content":"
Timestamp - To String
\n\n
= strftime("format", localtime(timestamp_1))
\n\nUsage:\n\n
from time import strftime\nfrom time import localtime\n\n= strftime("format", localtime(timestamp_1))
\n\nor\n\n
Convert to a datetime and then format.
\n\n\nExample:\n\n
from time import strftime\nfrom time import localtime\n\ntimestamp_2001 = 978325200\nformatted = = strftime("%Y-%m-%d %H:%M:%S", localtime(timestamp_2001))
\n\n\n\n"},{"id":"2rUy","level":1,"heading":"Datetime vs Timestamp","content":"
\n\nThere is no built in way to do this but the example above will do it.\nImplement a static method inside the EnumName class that will convert strings into enums.\n\n\n#1 - The static method that converts strings to Enums.\n\n#2 - Raises KeyError if not found.\n\n#3 - Define string to enum mappings here.\n\n\n\n"},{"id":"BUXG","level":1,"heading":"Dict","content":"
\n\nType: dict\n\n\nA collection of key value pairs.\nKeys can be any immutable type.\nInternally stored as a hash table.\n\n\n\n"},{"id":"eMNz","level":1,"heading":"Dict Operations","content":"
= {key_expression : value_expression for item in sequence_1}
\n\nReturns: dict\n\n\nIterates over a sequence, performing an operation on every item.\nReturns the result as dict.\n\n\nExample:\n\n
items = [1, 2, 3, 4, 5]\n\ndict_1 = {i : str(i) for i in items}
\n\n\n\n\n"},{"id":"bPY8","level":2,"heading":"Dict - Dict Comprehension - If Condition","content":"
Dict - Dict Comprehension - If Condition
\n\n
= {key_expression : value_expression for item in sequence_1 if condition}
\n\nReturns: dict\n\n\nIterates over a sequence, performing an operation on items that matth the if condition.\nReturns the result as dict.\n\n\nExample:\n\n
items = [1, 2, 3, 4, 5]\n\ndict_1 = {i : str(i) for i in items if i % 2 == 0}
\n\nReturns list of key value tuples.\n\n\n\n"},{"id":"7eRp","level":2,"heading":"Dict - Get Value","content":"
Dict - Get Value
\n\n
= dict_1[key_1] #1
\n\nor\n\n
= dict_1.get(key_1) #2
\n\nor\n\n
= dict_1.get(key_1, default_value)
\n\n\n#1 - Preferred style.\n\n#1 - Raises KeyError if not found.\n\n#2 - Returns None if not found.\n\n\nReturns the value of a dict.\n\n\nExample:\n\n
= {key : dict_1[key] for key in dict_1 if key in dict_2}
\n\nReturns: dict\n\n\nReturn a dict with only those items in common between dict_1 and dict_2.\n\n\n\n"},{"id":"ZTVm","level":2,"heading":"Dict - Is Dict?","content":"
\n\nReturns: dict\n\n\nReturn a new dict with all items of dict_1 and dict_2.\n\n\n#1 - Python 3.9+\n\n\n\n"},{"id":"ANAw","level":2,"heading":"Dict - Pop Value","content":"
Dict - Pop Value
\n\n
= dict_1.pop(key)
\n\nRemoves and returns the value for key.\n\n\n\n"},{"id":"xmck","level":2,"heading":"Dict - Size","content":"
= {key: dict_1[key] for key in dict_1 if key not in dict_2}
\n\nReturns: dict\n\n\nReturns a new dict containing only those items in dict_1 but not in dict_2.\n\n\n\n"},{"id":"k6Hx","level":2,"heading":"Dict - To List","content":"
\n\n\n\n"},{"id":"gL31","level":2,"heading":"List - List Comprehension","content":"
List - List Comprehension
\n\n
= [expression for value in list_1]
\n\nReturns: list\n\n\nIterates over a list or sequence, performing an operation on every item.\n\n\nExample:\n\n
list_1 = [1, 2, 3, 4, 5]\n\nlist_2 = [ i * 2 for i in list_1] # Returns [2, 4, 6, 8, 10]
\n\n\n\n\n"},{"id":"hCe5","level":2,"heading":"List - List Comprehension - If Condition","content":"
List - List Comprehension - If Condition
\n\n
= [expression for value in list_1 if condition]
\n\nReturns: list\n\n\nIterates over a list or sequence, performing an operation on those items that match the if condition.\n\n\nExample:\n\n
list_1 = [1, 2, 3, 4, 5]\n\nlist_2 = [ i * 2 for i in list_1 if i <= 3] # Returns [2, 4, 6]
\n\n\n\n"},{"id":"Y851","level":2,"heading":"List - List Comprehension, Nested","content":"
List - List Comprehension, Nested
\n\n
= [[expression for value in sublist] for sublist in list_1]
\n\nReturns: list[list]\n\n\nIterates over a list of lists or sequece of sequences, performing operations on every value in each sublist.\n\nReturns a list of lists.\n\n\nExample:\n\n
list_1 = [[1, 2], [3, 4]]\n\nplus_10 = [[value + 10 for value in sublist] for sublist in list_1]\n\n# Returns: [[11, 12], [13, 14]]
\n\n\n\n"},{"id":"fgZH","level":2,"heading":"List - List Comprehension, Nested, Flatten","content":"
List - List Comprehension, Nested, Flatten
\n\n
= [expression for sublist in list_1 for value in sublist]
\n\nReturns: list\n\n\nIterates over a list of lists or sequece of sequences, as if it were a flat list.\n\nReturns a flat list.\n\n\nExample:\n\n
list_1 = [[1, 2], [3, 4]]\n\nplus_10 = [value + 10 for sublist in list_1 for value in sublist]\n\n# Returns: [11, 12, 13, 14]
\n\n\nReturns the number of times value appears in list_1.\n\n\n\n"},{"id":"YBqs","level":2,"heading":"List - Count By Distinct Value","content":"
List - Count By Distinct Value
\n\n
from collections import Counter\n\n= Counter(list_1)
\n\n\nReturns: dict\n\n\nReturns a dictionary with every unique value and the number of times of that value is present.\n\n\n\n"},{"id":"nGs8","level":2,"heading":"List - Count Distinct Values","content":"
List - Count Distinct Values
\n\n
= len(set(list_1))
\n\n\nReturns the number of unique values in list_1.\n\n\n\n"},{"id":"PvC5","level":2,"heading":"List - Delete","content":"
\n\n\nCreates a shallow copy.\n\n\n\n"},{"id":"wqmh","level":2,"heading":"List - Duplicate - Deep Copy","content":"
List - Duplicate - Deep Copy
\n\n
from copy import deepcopy\n\n= deepcopy(list_1)
\n\n\nCreates a deep copy.\n\n\n\n"},{"id":"3Jc5","level":2,"heading":"List - Is Empty?","content":"
List - Is Empty?
\n\n
= not list_1
\n\n
if not list_1:\n\t...
\n\n\n\n"},{"id":"d4TQ","level":2,"heading":"List - Not Empty?","content":"
List - Not Empty?
\n\n
= bool(list_1)
\n\n
if list_1:\n\t...
\n\nUse bool() if you need to get a True/False value.\nThere is no need for bool() when using if....\n\n\n\n"},{"id":"PyhQ","level":2,"heading":"List - Is Equal?","content":"
List - Is Equal?
\n\n
= list_1 == list_2
\n\n
if list_1 == list_2:\n\t...
\n\n\nReturns True if both lists are of same size and contain the same values.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"qdJv","level":2,"heading":"List - Is List?","content":"
List - Is List?
\n\n
= type(item_1) is list
\n\n\n\n"},{"id":"33Hu","level":2,"heading":"List - Is Sublist?","content":"
List - Is Sublist?
\n\nUse Function:\n\n
def is_sublist(list_1, list_2):\n\n\tlist_1_len = len(list_1)\n\n\tfor i in range(len(list_2) - list_1_len + 1):\n\t\tif list_1 == list_2[i : i + list_1_len]:\n\t\t\treturn True\n\n\treturn False
\n\nCall:\n\n
= is_sublist(list_1, list_2)
\n\n\nReturns True if list_1 is a sublist of list_2.\n\nCreate the function is_sublist() above to test if a list is a sublist of another list.\n\n\nExample:\n\n
\n\nReturns the index of the first match.\n\nThrows ValueError if not found.\n\n\n\n"},{"id":"15eQ","level":2,"heading":"List - Flatten","content":"
List - Flatten
\n\nDefine:\n\n
def flatten(value):\n\n\tif type(value) is not list:\n\t\tyield value\n\t\treturn\n\n\tfor subvalue in value:\n\t\tyield from flatten(subvalue)
\n\nUse:\n\n
= list(flatten(list_1))
\n\n\nWill unwrap any combination of lists in lists into a flat list of values.\nPython has no built in way to do this but the flatten function above will do it.\n\n\nExample:\n\n
def flatten(value):\n\n\tif type(value) is not list:\n\t\tyield value\n\t\treturn\n\n\tfor subvalue in value:\n\t\tyield from flatten(subvalue)\n\n\nlist_1 = [1, 2, [[3, 4, [5, 6]], 7], [8, 9]]\n\nflattened = list(flatten(list_1))\n\n# Returns: [1, 2, 3, 4, 5, 6, 7, 8, 9]
\n\n\n\n"},{"id":"Rv8K","level":2,"heading":"List - Get Values Contained In Second List","content":"
List - Get Values Contained In Second List
\n\n
= [value for value in list_1 if value in list_2]
\n\n\nReturns a subset of list 1 where each value exists in list 2.\n\nUse a list comprehension with if to filter list 1 based on list 2.\nMaintains the original order.\n\n\n\n"},{"id":"mt0x","level":2,"heading":"List - Insert","content":"
\n\nReturns a new list in sorted order.\n\ncompare is a function that takes a list element as an argument, and returns it's comparable value.\n\n\n\n"},{"id":"pU1F","level":2,"heading":"List - Sort Reversed","content":"
List - Sort Reversed
\n\n
= sorted(list_1, reverse = True)
\n\nReturns: list\n\nSorts the list elements in reverse order.\n\n\n\n"},{"id":"kYHK","level":2,"heading":"List - Sort In Place","content":"
\n\n\nSorts the list in place.\n\ncompare is a function that takes a list element as an argument, and returns it's comparable value.\n\n\n\n"},{"id":"XMnV","level":2,"heading":"List - Unpack","content":"
List - Unpack
\n\n
item_1, item_2, ... = list_1
\n\nUnpacks the values in list_1 into separate variables.\nThe number of variables on the left must match the number of values in the list on the right.\n\nExample:\n\n
\n\n\n\n"},{"id":"UVnH","level":2,"heading":"List - From Dict","content":"
List - From Dict
\n\n
=list(dict_1.values())
\n\nReturns the values of dict_1 as a list.\n\n\n\n"},{"id":"aV2n","level":2,"heading":"List - To Dict","content":"
List - To Dict
\n\n
= {value:value for value in list_1}
\n\nReturns: dict\n\n\nUse a dict comprehension\nReturns a dict where every value is also the key to that value.\n\n\n"},{"id":"8252","level":2,"heading":"List - To Dict - Enumerated","content":"
List - To Dict - Enumerated
\n\n
= dict(enumerate(list_1))
\n\nReturns: dict\n\n\nReturns a dict where the value's list position maps to the value.\n\n\n\n"},{"id":"QQnF","level":2,"heading":"List - To Dict - From 2 Lists","content":"
List - To Dict - From 2 Lists
\n\n
= dict(zip(key_list, value_list)
\n\nReturns: dict\n\n\n\n"},{"id":"P7QX","level":2,"heading":"List - From Set","content":"
List - From Set
\n\n
= list(set_1)
\n\n\n\n"},{"id":"Nvtv","level":2,"heading":"List - To Set","content":"
List - To Set
\n\n
= set(list_1)
\n\nReturns a set with all duplicates removed.\n\n\n\n"},{"id":"xjbJ","level":2,"heading":"List - From Tuple","content":"
List - From Tuple
\n\n
= list(tuple_1)
\n\n\n\n"},{"id":"4v5E","level":2,"heading":"List - To Tuple","content":"
List - To Tuple
\n\n
= tuple(list_1)
\n\n\n\n"},{"id":"Qxyv","level":2,"heading":"List - To Any Type","content":"
List - To Any Type
\n\n
= list(map(conversion, list_1))
\n\n\nConverts elements in list_1 to a different type.\n\n\nExamples:\n\nConvert Strings to Integers:\n\n
\n\nUnordered group of unique items.\nContains no duplicates.\n\n\n#1 - Empty Set\n\n#2 - Pass in items as a tuple.\n\n\n\n"},{"id":"HKHe","level":1,"heading":"Set Operations","content":"
\n\n\nCreates a shallow copy of set_1.\n\n\n\n"},{"id":"fXKg","level":2,"heading":"Set - Duplicate - Deep Copy","content":"
Set - Duplicate - Deep Copy
\n\n
from copy import deepcopy\n\n= deepcopy(set_1)
\n\n\nCreates a deep copy of set_1.\n\n\n\n"},{"id":"v5MB","level":2,"heading":"Set - Get","content":"
Set - Get
\n\n
= next(iter(set_1))
\n\n\nReturns an item from the set.\nRepeating this call will return the same item!\n\n\n\n"},{"id":"AGKW","level":2,"heading":"Set - Get, Pop","content":"
Set - Get, Pop
\n\n
= set_1.pop()
\n\nRemoves and returns an item from the set.\n\n\n\n"},{"id":"gBLv","level":2,"heading":"Set - Is Empty?","content":"
Set - Is Empty?
\n\n
= not set_1
\n\n
if not set_1:\n\t...
\n\n\n\n"},{"id":"hAZQ","level":2,"heading":"Set - Not Empty?","content":"
Set - Not Empty?
\n\n
= bool(set_1)
\n\n
if set_1:\n\t...
\n\nUse bool() if you need to get a True/False value.\nThere is no need for bool() when using if....\n\n\n\n"},{"id":"3rSE","level":2,"heading":"Set - Is Equal?","content":"
Set - Is Equal?
\n\n
= set_1 == set_2
\n\n
if set_1 == set_2:\n\t...
\n\n\nReturns True if both sets are of same size and contain the same values.\n\n\nExample:\n\n
\n\n\nRemoves an item from the set.\n\n\nremove() throws an error if value does not exists.\ndiscard() ignores non-existent values.\n\n\n\n"},{"id":"Qw2R","level":2,"heading":"Set - Remove All","content":"
Set - Remove All
\n\n
set_1.clear()
\n\n\n\n"},{"id":"ktcs","level":2,"heading":"Set - Set Comprehension","content":"
Set - Set Comprehension
\n\n
= {expression for item in sequence_1}
\n\nReturns: set\n\n\nIterates over a sequence, performing an operation on every item.\nReturns the result as set.\n\n\nExample:\n\n
items = [1, 2, 3, 4, 5]\n\nset_ = {str(i) for i in items}
\n\n\n\n\n"},{"id":"RMXB","level":2,"heading":"Set - Set Comprehension - If Condition","content":"
Set - Set Comprehension - If Condition
\n\n
= {expression for item in sequence_1 if condition}
\n\nReturns: set\n\n\nIterates over a sequence, performing an operation on items that matth the if condition.\nReturns the result as set.\n\n\nExample:\n\n
items = [1, 2, 3, 4, 5]\n\nset_1 = {str(i) for i in items if i % 2 == 0}
\n\n\nReturns the number of elements in the set.\n\n\n\n"},{"id":"brdB","level":2,"heading":"Set - Sort","content":"
Set - Sort
\n\n
= sorted(set_1)
\n\n\n\n"},{"id":"Vh7P","level":1,"heading":"Set on Set Operations","content":"
Set on Set Operations
\n\n\n\n"},{"id":"tQba","level":2,"heading":"Set - Is Disjoint?","content":"
Set - Is Disjoint?
\n\n
= set_1.isdisjoint(set_2)
\n\nReturns true if set_1 and set_2 have no elements in common.\n\n\n\n"},{"id":"65JP","level":2,"heading":"Set - Is Subset?","content":"
Set - Is Subset?
\n\n
= set_2.issubset(set_1)
\n\nReturns true if set_2 is a subset of set_1.\n\n\nExample:\n\n
set_1 = {"one", "two", "three"}\nset_2 = {"one", "two"}\n\nif set_2.issubset(set_1):\n\tprint ("Is a subset.")\nelse:\n\tprint ("Not a subset.")\n\n# prints: Is a subset.
\n\n\n\n"},{"id":"nPm3","level":2,"heading":"Set - Is Superset?","content":"
Set - Is Superset?
\n\n
= set_2.issuperset(set_1)
\n\nReturns true if set_2 is a superset of set_1.\n\n\nExample:\n\n
set_1 = {"one", "two"}\nset_2 = {"one", "two", "three"}\n\nif set_2.issuperset(set_1):\n\tprint ("Is a superset.")\nelse:\n\tprint ("Not a superset.")\n\n# prints: Is a superset.
\n\nReturns a set of the elements in set_1 not in set_2.\n\n\n\n"},{"id":"6Ems","level":2,"heading":"Set - Intersection","content":"
Set - Intersection
\n\n
= set_1 & set_2
\n\nor\n\n
= set_1.intersection(set_2)
\n\nReturns a set containing only those values in both set_1 and set_2.\n\n\n\n"},{"id":"M85b","level":2,"heading":"Set - Symmetric Difference","content":"
Set - Symmetric Difference
\n\n
= set_1.symmetric_difference(set_2)
\n\n
= set_1.symmetric_difference(set_2, set_3, ...)
\n\nReturns a set of the elements in set_1 not in set_2 and the elements in set_2 not in set_1.\n\n\n\n"},{"id":"PjuT","level":2,"heading":"Set - Union","content":"
Set - Union
\n\n
= set_1 | set_2
\n\nor\n\n
= set_1.union(set_2)
\n\nReturns a set with all the values of set_1 and set_2.\nWill have no duplicates.\n\n\n\n"},{"id":"fHp3","level":1,"heading":"Tuple","content":"
Tuple
\n\n
= () # Empty Tuple\n\n= (value_1, value_2, ...)
\n\n\nType: tuple\n\n\nTuples are immutable arrays.\n\n\n\n"},{"id":"5BQ7","level":1,"heading":"Tuple Operations","content":"
\n\nUnpacks the values in tuple_1 into separate variables.\nThe number of variables on the left must match the number of values in the tuple on the right.\n\n\nExample:\n\n
\n\nSequence operations can be performed on any sequence type including lists, and tuples.\n\n\n\n"},{"id":"JbxP","level":2,"heading":"Index and Slicing Operations","content":"
Index and Slicing Operations
\n\n\n\n"},{"id":"W9ZJ","level":3,"heading":"Index and Slicing - Basics","content":"
Index and Slicing - Basics
\n\nSyntax:\n\n
first
= sequence_1[0]
\n
nth
= sequence_1[n]
# Indexes are 0 based
\n
second_last
= sequence_1[-2]
\n
last
= sequence_1[-1]
\n
\n
all
= sequence_1[:]
# Don't Use (Not Intuitive)
\n
all_but_first
= sequence_1[1:]
\n
all_but_last
= sequence_1[:-1]
\n
reversed
= sequence_1[::-1]
\n
\n
from
= sequence_1[start:]
\n
from_to
= sequence_1[start:end_plus_1]
\n
from_to_with_step
= sequence_1[start:end_plus_1:step]
\n
from_with_step
= sequence_1[start::step]
\n
to
= sequence_1[:end_plus_1]
\n
step_over
= sequence_1[::step]
\n
\n
m_to_nth
= sequence_1[m : n + 1]
\n\n\nExamples:\n\n
list_1 = [0, 1, 2, 3, 4]\n\n
first
= list_1[0]\t\t
# Returns 0
\n
second
= list_1[1]
# Returns 1
\n
...
\n
second_last
= list_1[-2]
# Returns 3
\n
last
= list_1[-1]
# Returns 4
\n
\n
all
= list_1[:]
# Returns [0, 1, 2, 3, 4] (Not Recommended)
\n
all_but_first
= list_1[1:]
# Returns [1, 2, 3, 4]
\n
all_but_last
= list_1[:-1]
# Returns [0, 1, 2, 3]
\n
reversed
= list_1[::-1]
# Returns [4, 3, 2, 1, 0]
\n
\n
from_1_to_3
= list_1[1:4]
# Returns [1, 2, 3]
\n
from_1_step_to_3
= list_1[1:4:2]
# Returns [1, 3]
\n
even
= list_1[::2]
# Returns [0, 2, 4]
\n
odd_from_1
= list_1[1::2]
# Returns [1, 3]
\n\n\n\n"},{"id":"JKrF","level":3,"heading":"Sequence - Get Value","content":"
Sequence - Get Value
\n\n
= sequence_1[index]
\n\n\nReturns one value from the sequence.\n\n\nExample:\n\n
\n\n* is returned as a list.\n_ is an element that is ignored.\n\n\n\n"},{"id":"VFXX","level":3,"heading":"Sequence - Destructure First Elements, Remainder","content":"
Sequence - Destructure First Elements, Remainder
\n\n
first, *remainder = sequence_1
\n\n
first, second, ... *remainder = sequence_1
\n\nReturns the first element, and the remainder as a list.\n\n\nExample:\n\n
\n\n\nReturns the number of times value appears in sequence_1.\n\n\n\n"},{"id":"48hu","level":3,"heading":"Sequence - Count Occurences With Counter","content":"
Sequence - Count Occurences With Counter
\n\n
from collections import Counter\n\n= Counter(sequence_1)
\n\n\nReturns: dict\n\n\nReturns a dictionary with every unique value and the number of times of that value is present.\n\n\n\n"},{"id":"hf58","level":3,"heading":"Sequence - Count By Distinct Value","content":"
Sequence - Count By Distinct Value
\n\n
= len(set(sequence_1))
\n\n\nReturns the number of unique values in sequence_1.\n\n\n\n"},{"id":"KMNQ","level":3,"heading":"Sequence - Duplicate","content":"
Sequence - Duplicate
\n\n
= sequence_1.copy()
\n\nCreates a shallow copy.\n\n\n\n"},{"id":"xPdQ","level":3,"heading":"Sequence - Duplicate - Deep Copy","content":"
Sequence - Duplicate - Deep Copy
\n\n
from copy import deepcopy\n\n= deepcopy(sequence_1)
\n\nCreates a deep copy.\n\n\n\n"},{"id":"pdjj","level":3,"heading":"Sequence - Is Empty?","content":"
Sequence - Is Empty?
\n\n
= not sequence_1
\n\n
if not sequence_1:\n\t...
\n\n\n\n"},{"id":"P4h9","level":3,"heading":"Sequence - Not Empty?","content":"
\n\nReturns the index of the first match.\n\n\n\n\n"},{"id":"1QQu","level":3,"heading":"Sequence - Iterate","content":"
Sequence - Iterate
\n\n
for value in sequence_1:\n\t...
\n\n\n\n"},{"id":"JyKx","level":3,"heading":"Sequence - To Dict","content":"
Sequence - To Dict
\n\n
= {value:value for value in sequence_1}
\n\nReturns: dict\n\n\nReturns a dict where every value is also the key to that value.\n\n\n\n"},{"id":"f12w","level":3,"heading":"Sequence - To Dict - Enumerated","content":"
Sequence - To Dict - Enumerated
\n\n
= dict(enumerate(sequence_1))
\n\nReturns: dict\n\n\nReturns a dict where the key to a value is the original index position of that value.\n\n\n\n"},{"id":"3Qq5","level":3,"heading":"Sequence - To Set","content":"
Sequence - To Set
\n\n
= set(sequence_1)
\n\nReturns a set with all duplicates removed.\n\n\n\n"},{"id":"Upk5","level":3,"heading":"Sequence - To Tuple","content":"
Sequence - To Tuple
\n\n
= tuple(sequence_1)
\n\n\n\n"},{"id":"1RTQ","level":3,"heading":"Sequence - To Iterator","content":"
Sequence - To Iterator
\n\n
= iter(sequence_1)
\n\nTurns any sequence type into an iterator.\n\n\n\n"},{"id":"qd4T","level":2,"heading":"Sequence Functions","content":"
\n\nReturns true if all elements of boolean_sequence_1 evaluate to True.\nThis function short-circuits when a False value is reached.\n\nUse test_function to return the True / False value for sequence_1 elements.\n\n\n\n"},{"id":"PEVL","level":3,"heading":"Sequence - Any","content":"
Sequence - Any
\n\n
= any(boolean_sequence_1)
\n\nor\n\n
= any(map(test_function, sequence_1))
\n\nReturns true if any element of boolean_sequence_1 evaluates to True.\nThis function short-circuits when a True value is reached.\n\nUse test_function to return the True / False value for sequence_1 elements.\n\n\n\n"},{"id":"WuEN","level":3,"heading":"Sequence - Average","content":"
Sequence - Average
\n\n
= sum(sequence_1) / len(sequence_1)
\n\n\nReturns the average of the values in a list.\n\n\nExample:\n\n
\n\nReturns: enumerate\n\t\t(generator of index, value tuples)\n\n\nThe enumerate function returns a generator.\n\nThat generator returns an index, value tuple for each entry in the sequence.\nThe index is the position in the sequence (zero based).\nThe value is the value in the sequence at that position.\n\n\nExample:\n\n
list_1 = ["zero", "one", "two"]\n\nfor index, value in enumerate(list_1):\n\tprint (index, value)
\n\nReturned Type: filter\n\n\nReturns all values where test_function(value) == True.\n\nReturns a filter that will return a subset of sequence_1.\nFilters are lazy iterators.\nValues are evaluated and returned one at a time, and only when requested.\n\n\nExamples:\n\nUsing a Filter Function:\n\n
\n\n\nUsed by filter() to determine which values to return.\nMust return True or False.\nTrue values will be returned by filter()\n\n\n\n"},{"id":"EVhE","level":4,"heading":"Filter - To List","content":"
\n\nReturns: map\n\n\nReturns a map of sequence_1 values passed through mapping_function.\n\nMaps are lazy itorators. Wrap with list() to get actual values.\n\n\nExample:\n\n
def add_10(value):\n\treturn value + 10\n\nlist_1 = [1, 2, 3]\n\nmapped = list(map(add_10, list_1))\n\n# Returns: Map of 11, 12, 13.
\n\nCalculates a value base on previous_result and next_value.\n\nFor the first calculation, previous_result will either be:\n\tinitial_value if provide, or\n\tfirst_value the first value in the sequence.\n\n\n\n"},{"id":"B8V9","level":3,"heading":"Sequence - Shuffle","content":"
Sequence - Shuffle
\n\n
from random import shuffle\n\nshuffle(sequence_1)
\n\nRandomizes a sequence in place.\n\n\n\n"},{"id":"nZJ6","level":3,"heading":"Sequence - Sort","content":"
Sequence - Sort
\n\n
= sorted(sequence_1)
\n\n
= sorted(sequence_1, key = compare)
\n\nReturns: list\n\nReturns a new sorted list from sequence_1.\n\ncompare is a function that takes a sequence element as an argument, and returns it's comparable value.\n\n\nExample:\n\n
\n\nReturns: zip(*iterable)\n\nZips two or more sequences or iterables together.\nThe returned zip object is iterable and returns tuples.\nEach tuple contains the element from each sequence at that position.\nIf the sequences are different sizes, returns the shortest size.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"VHdG","level":3,"heading":"Sequence - Zip Unequal Sized Lists","content":"
Sequence - Zip Unequal Sized Lists
\n\n
= zip_longest(sequence_1, sequence_2)
\n\nUsage:\n\n
from itertools import zip_longest\n\n= zip_longest(sequence_1, sequence_2)
\n\nReturns: zip_longest\n\n\nReturns an iterable that returns tuples from each list.\n\nReturns None where shorter lists have no value.\n\n\nExample:\n\n
from queue import Queue\n\n= Queue()\n= Queue(max_size) #1
\n\nAsynchronous first in first out queue.\n\n#1 - Defins the maximum number of elements in the queue.\n\n\n\n"},{"id":"Bak7","level":2,"heading":"Queue Operations","content":"
\n\n\n\n"},{"id":"Lf0T","level":3,"heading":"Queue - Get Next","content":"
Queue - Get Next
\n\n
= queue_1.get() #1
\n\nor\n\n
= queue_1.get_nowait() #2
\n\n\nGet next item.\n\n\n#1 - If no items, waits until one becomes available.\n\n#2 - If no items, raises QueueEmpty.\n\n\n\n"},{"id":"wgXr","level":3,"heading":"Queue - Is Empty?","content":"
Queue - Is Empty?
\n\n
= queue_1.empty()
\n\nReturns: bool\n\nReturns True if empty.\n\n\n\n"},{"id":"bJYz","level":3,"heading":"Queue - Is Full?","content":"
Queue - Is Full?
\n\n
= queue_1.full()
\n\nReturns: bool\n\nReturns True if the queue is full and can't take any more items.\n\n\n\n"},{"id":"uAHE","level":3,"heading":"Queue - Maximum Size","content":"
Queue - Maximum Size
\n\n
= queue_1.maxsize
\n\n\nReturns the maximum allowed size of the queue.\nReturns 0 if no maximum set.\n\n\n\n"},{"id":"qCrT","level":3,"heading":"Queue - Size","content":"
Queue - Size
\n\n
= queue_1.qsize()
\n\nReturns the number of items in the queue.\n\n\n\n"},{"id":"GHMg","level":1,"heading":"Conversions","content":"
Conversions
\n\n\n\n"},{"id":"69LC","level":2,"heading":"ASCII Code - To String Character / chr()","content":"
ASCII Code - To String Character / chr()
\n\n
= chr(ascii_code)
\n\nExample:\n\n
string_1 = chr(67) # Returns 'C'
\n\n\n\n"},{"id":"x3BQ","level":2,"heading":"Base64 - To Bytes","content":"
Base64 - To Bytes
\n\n
from base64 import b64decode\n\n= b64decode(bytes_1)
\n\nRetuns: bytes\n\n\nDecodes a base64 encoded byte array.\nReturns another byte array.\n\n\nExample:\n\n
\n\n#1 - Prints '696e206279746573'\n\n\n\n"},{"id":"N3Mh","level":2,"heading":"Bytes - To Int","content":"
Bytes - To Int
\n\n
= int.from_bytes(bytes_1, "big")
\n\nUse "big" for bytes with the most significant byte first.\nUse "little" for bytes with the most significant byte first.\n\n\n\n"},{"id":"5uFJ","level":2,"heading":"Bytes - To String","content":"
Bytes - To String
\n\n
= bytes_1.decode("utf-8")
\n\n\n\n"},{"id":"ush7","level":2,"heading":"Complex Number - To String","content":"
Complex Number - To String
\n\n
= str(complex_1)
\n\n\n\n"},{"id":"V11K","level":2,"heading":"Float - To Decimal","content":"
Float - To Decimal
\n\n
from decimal import Decimal\n\n= Decimal(float_value)
\n\n\nCreates an immutable decimal value.\n\n\nExample:\n\n
from decimal import Decimal\n\ndecimal_1 = Decimal(12.34)\n\nprint(decimal_1)\n\n# Prints 12.339999999999999857891452847979962825775146484375
\n\n\n\n"},{"id":"t8GB","level":2,"heading":"Float - To Integer","content":"
Float - To Integer
\n\n
= int(float_value)
\n\nExample:\n\n
int_1 = int(1234.567) # Returns 1234
\n\n\n\n"},{"id":"FayQ","level":2,"heading":"Float - To String","content":"
\n\n\n\n"},{"id":"Qc0E","level":2,"heading":"String Character - To ASCII Code / ord()","content":"
String Character - To ASCII Code / ord()
\n\n
= ord('character')
\n\ncharacter must be a single letter string.\n\n\nExample:\n\n
ascii_code = ord('C')\n\n# Returns 67
\n\n\n\n"},{"id":"rJfY","level":2,"heading":"String - To Boolean","content":"
String - To Boolean
\n\n
= string_value.lower() in ['t', 'true', 'y', 'yes', 1]
\n\nReturns true if string_value is one of 't', 'true', 'y', 'yes', or 1.\nCase is ignored.\n\n\n"},{"id":"zGGn","level":2,"heading":"String (Empty / Not Empty) - To Boolean","content":"
String (Empty / Not Empty) - To Boolean
\n\n
= bool(string_value)
\n\n\nTests for empty string.\n\nEmpty String = False\nOtherwise = True\n\n\n\n"},{"id":"eXNv","level":2,"heading":"String - To Bytes","content":"
String - To Bytes
\n\n
= string_1.encode()
\n\n
= string_1.encode('utf-8')
\n\n\n\n"},{"id":"tMGS","level":2,"heading":"String - To Complex Number","content":"
String - To Complex Number
\n\n
= complex("1 + 2j")
\n\n\n\n"},{"id":"349U","level":2,"heading":"String - To Decimal","content":"
String - To Decimal
\n\n
from decimal import Decimal\n\n= Decimal('10.99')
\n\n\nCreates an immutable decimal value.\nKeeps the precision the decimal was created to.\n\n\nExample:\n\n
from decimal import Decimal\n\ndecimal_1 = Decimal('12.34')\n\nprint(decimal_1)\n\n# Prints 12.34
\n\n\n\n"},{"id":"Lh7J","level":2,"heading":"String - To Float","content":"
String - To Float
\n\n
= float(float_string)
\n\nExample:\n\n
float_1 = float("123.3")
\n\n\n\n"},{"id":"dury","level":2,"heading":"String - To Integer","content":"
String - To Integer
\n\n
= int(string_value)
\n\nExample:\n\n
int_1 = int("123")
\n\n\n\n"},{"id":"pwEY","level":2,"heading":"String - To List","content":"
String - To List
\n\n
= [character for character in string_1]
\n\n\nReturns: list of str\n\n\nConverts a string to a list of characters.\n\n\nExample:\n\n
string_1 = 'abc'\n\nlist_1 = [character for character in string_1]\n\n# Returns: ['a', 'b', 'c']
\n\n\n\n"},{"id":"Sa8a","level":2,"heading":"String - To Set","content":"
String - To Set
\n\n
= set(string_1)
\n\n\nReturns: set of str\n\n\nConverts a string to a set of characters.\n\n\nExample:\n\n
\n\nAllows a resource's lifecycle to be handled correctly.\nThe context manager will open the resource using with\nand will close it correctly when exiting the block.\nNo close() method needs to be called, even if an exception is thrown.\n\n\n"},{"id":"ykZB","level":2,"heading":"Context Manager - Define","content":"
Context Manager - Define
\n\n
class ManagedResource1:\n\n\tdef __enter__ (self): # Called At Creation\n\t\t...\n\n\tdef __exit__ (self, type, value, traceback): # Called At Completion\n\t\t...
\n\n\nAllows a class to be used as a managed resource.\n\ntype, value, traceeback will be populated when an exception is raised. value will contain the exception.\n\n\n\n"},{"id":"XpYp","level":2,"heading":"Context Manager - Use / With","content":"
Context Manager - Use / With
\n\n
with ManagedResource1() as resource_item_1:\n\t...
\n\nReference the resource using resource_item_1.\nresource_item_1 is automatically closed at the end of the block.\n\n\n\n"},{"id":"Gtxq","level":1,"heading":"Error Handling","content":"
\n\nDefines a new exception type.\nInherit from Exception.\n\n\n\n"},{"id":"S4vb","level":3,"heading":"Raise","content":"
Raise
\n\n
raise Exception1()
\n\n
raise Exception1() from exception_1\t\t#1
\n\n#1 - Chains Stack Traces From exception_1\n\n\n\n"},{"id":"dtKA","level":3,"heading":"Try Except","content":"
Try Except
\n\n
try:\n\t...\nexcept Exception1 as exception:\n\t...\nelse:\n\t...\nfinally:\n\t...
\n\n
try:\n\t...\n\nexcept Exception1:\n\t# Catches Exception1 (#1)\n\t...\n\nexcept Exception2 as exception_2\n\t# Catches Exception2, Reference with exception_2\n\t...\n\nexcept Exception as exception_3\n\t# Catches Any Exception\n\t...\n\nelse:\n\t# Called if no exception thrown.\n\t...\n\nfinally:\n\t# Always Executed (#2)\n\t...
\n\nCatches an exception raised in the try part of the block.\nAll subclasses of a exception are caught in the same block as the exception.\n\n#1 - No exception variable assignd so exceptions can not be referenced in this block.\n\n#2 - Always executes even if an exception is thrown.\n\n\n\n"},{"id":"DkWS","level":3,"heading":"Try Except - Basic","content":"
Try Except - Basic
\n\n
try:\n\t...\nexcept Exception1 as exception:\n\t...\nexcept Exception2 as exception:\n\t...\nfinally:\n\t...
try:\n\t...\nexcept Exception1 as exception:\n\t...\nelse:\n\t...\nfinally:\n\t...
\n\n\n\n"},{"id":"wmaS","level":3,"heading":"Try Except - Single Line Multiple Exceptions","content":"
Try Except - Single Line Multiple Exceptions
\n\n
try:\n\t...\n\nexcept (Exception1, Exception2):\n\t...\n\nexcept (Exception3, Exception4) as error\n\t...
\n\n\nExample:\n\n
try:\n\tvalue = input("Enter number: ")\n\n\tif not value:\n\t\traise ValueError("Must enter a value.")\n\n\tif not value.isdigit():\n\t\traise TypeError("Must be a number.")\n\nexcept (TypeError, ValueError):\n\t...
\n\n\n\n"},{"id":"HUgB","level":3,"heading":"Exception - Get Message","content":"
Exception - Get Message
\n\n
= str(exception_1)
\n\nWorks in some circumstances:\n\n
= exception_1.args[0]
\n\nReturns the error message.\n\n\n\n"},{"id":"W17w","level":3,"heading":"Exception - Get Stack Trace","content":"
\n\nUse to indicate an iterator or generator has completed.\n\n\n\n"},{"id":"UBFQ","level":3,"heading":"Exception - TypeError","content":"
Exception - TypeError
\n\n
TypeError
\n\nUse to indicate invalid or None type.\n\n\n\n"},{"id":"x5ZE","level":3,"heading":"Exception - ValueError","content":"
Exception - ValueError
\n\n
ValueError
\n\nUse when type is correct but value is outside the expected range.\nUse this for request validations.\n\n\n\n"},{"id":"Vuqm","level":1,"heading":"Functions","content":"
response_1 = function_1(arg_1_name = arg_1, ...)\t\t# With Named Arguments
\n\nFunctions are stored as global attributes.\nFunction definitions can be monkey patched by changing the global definition.\nFunctions are first class objects and can be passed as values.\n\n\n\n"},{"id":"VfLB","level":2,"heading":"Function - Details","content":"
\n\nkwargs Type: dict\n\nThe caller arguments are placed in a dictionary.\nThe caller must use named arguments.\n"kwargs" is the name by convention for this argument.\n\nkwargs = key word arguments\n\n\nExample:\n\n
def say(**kwargs):\n\tprint(kwargs['greeting'], kwargs['name'])\n\nsay(greeting = "Hi", name = "John")
\n\n\n\n"},{"id":"rARh","level":3,"heading":"Function - Arguments - As Tuple","content":"
Function - Arguments - As Tuple
\n\n
def function1(*args):\n\t...\n\tvalue_1 = args[index_1]\t\t\t\t# Reference an Argument\n\t...
\n\nargs Type: tuple\n\nThe caller arguments are placed in a tuple.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"jgbr","level":3,"heading":"Function - Call - With Sequence","content":"
Function - Call - With Sequence
\n\n
function_1(*sequence_1)
\n\nPass sequence_1 to the function as it's arguments.\nUnpacks the sequence into arguments in order they are declared in the function signature.\n\n\nExample:\n\n
\n\n\n#1 - Scope - inner_function is visible to parent_function only.\n\n\n\n"},{"id":"vbfK","level":3,"heading":"Inner Function - Closure","content":"
Inner Function - Closure
\n\nAn inner function has read access to it's parent's variables.\nThere are in scope due to the function 'closing' over the parent's environment.\n\n\nExample:\n\n
\n\nWhen a function is decorated and then called, decorated_function will be called thorugh wrapper().\n\n#1 - Place pre-function call code here.\n#2 - Calls decorated_function.\n#3 - Place post-function call code here.\n\n\n\n"},{"id":"97Y0","level":3,"heading":"Decorator - Define - Passing Arguments","content":"
\n\n\nWhen a function is decorated and then called, decorated_function will be called thorugh wrapper().\n\n#1 - Captures calling statement's arguments.\n\n#2 - Calls decorated_function and passes arguments.\n\n\n\n"},{"id":"C5wH","level":3,"heading":"Decorator - Define - Return Result","content":"
\n\n\nPasses arguments to the decorator itself.\n\nThis uses an outer decorator factory.\nUse this decorator factory as the @decorator name.\n\n\nExample:\n\n
from functools import partial\n\npartial_function_1 = partial(function_1, arg_1_value)
\n\nReturns the function with some arguments applied.\nArguments are applied to arguments from first to last.\nCall the returned function with additional arguments to make the actual call.\n\nAlso Called: Currying\n\n\nExample:\n\n
\n\n\nAll class functions and variables are public by default.\n\nFunction overloading is NOT supported.\n- use arguments default values to solve this.\n- use type checking to catch incorrect arguments.\n\nClasses are mutable.\nClass methods are stored as attributes and can be monkey patched.\n\nInstance variables must be created in a class function and attached to self.\n\nThe self argument is required for all class functions.\n- self is called self by convention.\n\n\n\n"},{"id":"e6Z2","level":3,"heading":"Class - Define","content":"
Class - Define
\n\n
class Class1:\n\t...
\n\nWith Constructor:\n\n
class Class1:\n\n\t def __init__(self, arg_1, ...):\n\n\t\tself.property_1 = ...
class Class1:\n\tdef __init__(self, arg_1, ...):\n\t\t...
\n\nDefine the constructor with the __init__ method.\n\nDefine instance arguments in the constructor.\n\n\n\n"},{"id":"CaCf","level":3,"heading":"Class - Define - With Inheritance","content":"
Class - Define - With Inheritance
\n\n
class Subclass1(Superclass1):\n\t...
\n\nInitializing Parent:\n\n
class Subclass1(Superclass1):\n\n\tdef __init__(self, ...):\n\t\tsuper().__init__()\n\t\t...
\n\nInitializing Parent With Arguments:\n\n
class Subclass1(Superclass1):\n\n\tdef __init__(self, ...):\n\t\tsuper().__init__(arg_1, ...)\n\t\t...
\n\n\n"},{"id":"TCWw","level":3,"heading":"Class - Define - With Multiple Inheritance","content":"
Class - Define - With Multiple Inheritance
\n\n
class Subclass1(Superclass1, Superclass2, ...):\n\t...
\n\nPriority is from left to right.\nSuperclass1's members take precedence over other super classes.\n\n\n\n"},{"id":"r0Gu","level":3,"heading":"Class - Call Superclass","content":"
Class - Call Superclass
\n\n
super().__init__()
\n\n
class class1(Superclass1):\n\n\tdef __init__(self, ...):\n\t\tsuper().__init__(arg_1, ...)\n
\n\n\n\n"},{"id":"cuGG","level":3,"heading":"Class - New Instance","content":"
class Class1:\n\n\tdef some_method(self):\n\n\t\tself.variable_1 = value\t\t\t# Create / Set\n\n\t\t= self.variable_1\t\t\t\t# Get
\n\nGet:\n\n
= class_1.variable_1
\n\nSet:\n\n
class_1.variable_1 = new_value
\n\nDefine instance variables in the constructor so they are always available.\nReference instance variable internally in the class with 'self.' .\nReference instance variable through instance name outside of class.\n\n\n\n"},{"id":"bzeZ","level":3,"heading":"Class - Instance Method","content":"
Class - Instance Method
\n\nDefine:\n\n
class Class1:\n\n\tdef method_1(self, arg_1, ...):\n\t\t...
\n\nCall Inside Class:\n\n
class Class1:\n\n\tdef ...(self):\n\n\t\tself.method_1(arg_1, ...)
\n\nCall Outside Class:\n\n
class_1.method_1(arg_1, ...)
\n\nReference instance methods internally in the class with 'self.' .\nReference instance methods externally through the instance name (class_1 in this case).\n\n\n\n"},{"id":"gXt4","level":3,"heading":"Class - Class Variable","content":"
Class - Class Variable
\n\nDefine:\n\n
class Class1:\n\tvariable_1 = value
\n\nGet:\n\n
= Class1.variable_1
\n\nSet:\n\n
Class1.variable_1 = new_value
\n\n\nDefines a class or static variable.\n\nThis variable is associated with the class and not an instance of the class.\nRefer to the variable through the class name only.\n\n\n\n"},{"id":"W6fN","level":3,"heading":"Class - Class Method","content":"
Class - Class Method
\n\n
@classmethod\nmethod_1(...)
\n\nDefine:\n\n
class Class1:\n\n\t@classmethod\t\t\t\t\t#1\n\tmethod_1(cls, arg_1, ...):\t\t#2\n\t\tcls.class_variable = value\n\t\t...
\n\nCalling:\n\n
Class1.method_1(arg_1, ...)
\n\n\nDefines a method that acts on the class and not an instance of the class.\n\n\nDefine with @classmethod.\nReference the method using the class name (Class1 in this case).\n\n\nThis is useful if you need to know exactly what type of class was instantiated.\n\n\n#1 -@classmethod defines a class method.\n\n#2 - The class is passed in as cls.\n\n\n\n"},{"id":"z5zd","level":3,"heading":"Class - Static Method","content":"
Class - Static Method
\n\n
@staticmethod\nmethod_1(...)
\n\nDefine:\n\n
class Class1:\n\n\t@staticmethod\n\tmethod_1(arg_1, ...):\n\t\t...
\n\nCalling:\n\n
Class1.method_1(arg_1, ...)
\n\n\nDefines a static method, one that is called on the class and not on an instance of the class.\n\nDefine with @staticmethod.\nReference through the class name.\nCan not update class variables.\n\n\n\n"},{"id":"auQL","level":3,"heading":"Class - Class Method vs Static Method","content":"
Class - Class Method vs Static Method
\n\nClass Method:\n\nUse for class level methods than work with the class itself.\n\n\n\nStatic Method:\n\nUse for utility methods that are related to the class but do not interact with the class.\n\n\n\n"},{"id":"QG9s","level":3,"heading":"Class - Equals - Is Type or Subtype?","content":"
Class - Equals - Is Type or Subtype?
\n\n
= isinstance(item_1, Class1)
\n\nReturns true if item_1 is a type or a subtype of Class1.\n\n\n\n"},{"id":"KqcP","level":3,"heading":"Class - Equals - Is Same Class?","content":"
Class - Equals - Is Same Class?
\n\n
= type(item_1) is Class1
\n\nReturns true if item_1 is the class Class1.\nDoes not match subtypes.\n\n\n\n"},{"id":"PDFS","level":3,"heading":"Class - Equals - Is Same","content":"
Class - Equals - Is Same
\n\nImplement Method:\n\n
def __eq__(self, other):
\n\nCompare:\n\n
= item1 == item2
\n\n
if item1 == item2:
\n\n\nImplement __eq__() to allow class instances to be compared with equals (==).\n\n\nExample:\n\n
class Class1:\n\n\tdef function_1(self):\n\n\t\tself._variable_1 = ...\n\t\t... = self._variable_1\n\n\t\tself.function_1()
\n\n\nself is the current instance of the class.\n\nReference any instance variables or functions using self.\nself must be the first argument in any non static functions.\nDo not pass self to a non static function. It will be passed automatically.\n\n\n\n"},{"id":"ydPw","level":3,"heading":"Class - To String","content":"
Class - To String
\n\n
class Class1:\n\t...\n\tdef __repr__(self):\n\t\treturn string_representing_class
\n\n
= class_1__repr__())
\n\n
= repr(class_1)\t\t\t\t\t\t\t# Equivalent to .__repr()
\n\nOverride __repr__ to create class string.\n\n\n\n"},{"id":"sYZs","level":2,"heading":"Abstract Class","content":"
Abstract Class
\n\n\n\n"},{"id":"tV20","level":3,"heading":"Abstract Class - Define","content":"
Abstract Class - Define
\n\n
from abc import ABC, abstractmethod\n\nclass AbstractClass1(ABC):\n\n\t@abstractmethod\n\tdef abstract_method_1(self):\n\t\tpass
\n\n\n\n"},{"id":"D7th","level":3,"heading":"Abstract Class - Use","content":"
Abstract Class - Use
\n\n
class Subclass1(AbstractClass1):\n\n\tdef abstract_method_1(self):\t\t# Implement Abstract Method\n\t\t...
\n\nDefines class functions as if they were class variables.\nUse to encapsulate mutation of internal variables.\n\n\n\n"},{"id":"rjkw","level":3,"heading":"Class Property - Define","content":"
\n\n\nDefines a method to work like a property (instance variable).\n\nThe decorator @property does not need to be imported.\n\n\n\n"},{"id":"GSts","level":3,"heading":"Class Property - Use","content":"
\n\nCreates or updates a class attribute.\n\nAccess using class_1.attribute_name\n\n\n\n"},{"id":"tSCK","level":3,"heading":"Class - Attribute - Names","content":"
Class - Attribute - Names
\n\n
= class_1.__dict__.keys()
\n\n
= list(class_1.__dict__.keys())\t\t\t# As List
\n\n\n\n"},{"id":"WXe9","level":3,"heading":"Class - Attributes - To Dict","content":"
# Unaltered Class:\nclass Class1:\n def method_to_patch(self):\n ...\n\n# Patch Function:\ndef patch_1(self):\n ...\n\nitem_1 = Class1()\n\n# Apply patch to the class:\nClass1.method_to_patch = patch_1\n\nitem_1.method_to_patch()
\n\n\nChanges the behaviour of a method at runtime.\n\nApplies the patch to the class, not the instance.\nThis will affect all instances of the class, current and future.\n\n\nExample:\n\n
class Messanger:\n def print_message(self):\n print("Original message.")\n\ndef print_message_patch(self):\n print("Patched message.")\n\nmessage_1 = Messanger()\nmessage_1.print_message()\n\nMessanger.print_message = print_message_patch\nmessage_1.print_message()\n\n# Prints:\n# Original message.\n# Patched message.
from types import MethodType\n\ndef patch_1(self):\n ...\n\ninstance_1.method_to_patch = MethodType(patch_1, instance_1\n\ninstance_1.method_to_patch()
\n\n\nChanges the behaviour of an instance method at runtime.\n\nThis only affects this instance. Neither the underlying class or other instances are affected.\nUsing MethodType assures the function is bound correctly to the instance and the self value is passed in correctly.\n\n\nExample:\n\n
if item_1 in class_1:\t\t\t\t\t# Using with in\n\t...
\n\nOverride __contains__ to use class with in operator.\nReturn true if key is in the class.\n\n\n\n"},{"id":"vQUK","level":1,"heading":"Iterable, Iterator","content":"
\n\n\nDefines a class as iterable.\n\n\n#1 - Implement __iter__() to make the class iterable.\n\n#2 - Return an iterator for the class data.\n\n\nExample:\n\n
\n\n\nThis class is both an iterator and an iterable.\n\n\n#1, #2 - Implement __iter__() and __next__() to make this both an iterabale and an iterator.\n\n#3 - Raise StopIteration to indicate iterating is complete.\n\n#4 - Return the next item in the iteration with __next__().\n\n\n\n"},{"id":"eNQR","level":3,"heading":"Iterable - From Dict","content":"
class Iterator1:\n\n def __next__(self): #1\n\n If at_the_end:\n raise StopIteration #2\n else:\n return next_item#3
\n\n\nDefines an iterator class.\n\n\n#1 - Implement __next__() to make this an iterator.\n\n#2 - Raise StopIteration to indicate iterating is complete.\n\n#3 - Return the next item in the iteration with __next__().\n\n\nExample:\n\n
\n\n\n\n"},{"id":"WdeA","level":3,"heading":"Iterator - Get Next","content":"
Iterator - Get Next
\n\n
= next(iterator_1) #1
\n\nor\n\n
= next(iterator_1, default_value) #2
\n\n\nReturns the next value from an iterator.\n\n\n#1 - When no more elements, raises StopIteration.\n\n#2 - When no more elements, returns default_value.\n\n\n\nExample:\n\n
values = iter([1, 2, 3])\n\nwhile value := next(values):\n print(value)
\n\nA generator is a function wrapped in an iterable.\nThe function should act like an iterator (eg: returns results with yield).\n\n\n\n"},{"id":"tz59","level":2,"heading":"Generator Expression","content":"
Generator Expression
\n\n
= (expression for item in sequence_1)
\n\n
= (expression for item in sequence_1 if condition)
\n\nReturns: generator\n\n\nSimilar to a list comprehension but are evaluated lazily.\nLazy iterators - Values are evaluated and returned one at a time, and only when requested.\n\n\nExamples:\n\n
list_1 = [1, 2, 3, 4, 5]\n\ngenerator = (i * 2 for i in list_1)\n\nprint(list(generator))\t\t\t\t\t\t\t# Prints [2, 4, 6, 8, 10]
\n\n
list_1 = [1, 2, 3, 4, 5]\n\ngenerator = (i * 2 for i in list_1 if i <= 3)\n\nprint(list(generator))\t\t\t\t\t\t\t# Prints [2, 4, 6]
\n\n\n\n"},{"id":"H5J1","level":2,"heading":"Generator Expression - Get Next","content":"
Generator Expression - Get Next
\n\n
= next(generator_1)
\n\n\n\n"},{"id":"t49R","level":2,"heading":"Generator Expression - To List","content":"
def some_function():\t\t\t\t\t#1\n\n\tfor list_value in list_1:\n\t\tyield list_value\t\t\t\t#2\n\n\nfor value in some_function():\t\t\t#3\n\t...
\n\nReturns: generator\n\n#1 -yield must be defined inside a function.\n\n#2 -yield temporarily suspends operation and returns list_value.\n\n#3 - The function returns a generator that can be used to iterate over the yield values.\n\n\nyield turns a function into a generator.\n\nThe generator returns a result every time yield is executed, suspending the function.\nExecution continues when the generator is called again.\n\n\nExample:\n\n
Define:\n\nfrom math import factorial\n\ndef factorial_series(n):\n\tfor i in range (n + 1):\n\t\tyield factorial(i)\n\n\nUse:\n\nfor value in factorial_series(4):\n\tprint(value)
\n\n\nAllows the function to delegate part of its generator results to a 2nd generator.\n\nMust be inside a function.\nThis is very useful when using recursion.\n\n\n"},{"id":"w9zp","level":1,"heading":"Packages, Modules","content":"
\n\nCreate the file in the subdirectory that contains modules.\n\nPackage directories are typically defined with the presence of '__init__.py'.\nThis file is not required as of Python 3.3.\n__init__.py can be empty.\nThis file is executed when the package is imported.\n\n\n\n"},{"id":"GdP4","level":2,"heading":"Package Directory - Name","content":"
Package Directory - Name
\n\nThe package name is the directory name.\n\n\n\n"},{"id":"V5qQ","level":2,"heading":"Module - Name","content":"
Module - Name
\n\n
= __name__
\n\nReturns the name of the current module (name of the python file without the extension).\n\n'__main__':\nIf the module is the starting module of the application, __name__ will be '__main__'.\n\n\n\n"},{"id":"MTBG","level":2,"heading":"Import - Module / Package","content":"
Import - Module / Package
\n\nImport:\n\n
import module_1
\n\n
import package_1.subpackage_1.module_1
\n\n
from package_1.subpackage_1 import module_1
\n\n
from package_1.subpackage_1 import module_1 as alias
\n\n\nUse:\n\n
module_1.item_1...
\n\n\nImports a module or package into the current namespace.\n\nThis uses absolute imports and must contain the full package path to the project root.\n\n\n\n"},{"id":"7UA1","level":2,"heading":"Import - Module / Package - Relative Import","content":"
Import - Module / Package - Relative Import
\n\nRelative To Parent:\n\n
from .module import name
\n\nRelative To Grandparent:\n\n
from ..module import name
\n\nParent of Current Package:\n\n
from .. import module
\n\n\nImports a module relative to the current module.\n\nOnly available with from x import y syntax.\nImports must be within toplevel_package only. Not other packages.\n\n\n\n"},{"id":"vv88","level":2,"heading":"Import - Package - __init__.py","content":"
Import - Package - __init__.py
\n\nThe file __init__.py is executed when a package is imported as a module.\n\n
import package_1
\n\n\n\n"},{"id":"wNYq","level":2,"heading":"Import - Class / Function","content":"
\n\n\n\n\n"},{"id":"SYRp","level":3,"heading":"Log 1 Plus (log1p)","content":"
Log 1 Plus (log1p)
\n\n
from math import log1p\n\n= log1p(x)
\n\nEquivalent to log(1 + x).\n\nUses the natural log (base e).\n\n\n\n"},{"id":"JQp6","level":3,"heading":"Power","content":"
Power
\n\n
= x ** y
\n\nOr\n\n
= pow(x, y)
\n\n\nReturns x to the power of y.\n\npow() is a standard function. No import required.\n\n\n\n"},{"id":"Wx1T","level":3,"heading":"Square","content":"
Square
\n\n
= x ** 2
\n\nOr\n\n
= pow(x, 2)
\n\n\npow() is a standard function. No import required.\n\n\n\n"},{"id":"36T4","level":3,"heading":"Square Root","content":"
\n\n\n\n"},{"id":"QU85","level":3,"heading":"Json String - From JSON String","content":"
Json String - From JSON String
\n\n
from json import loads\n\ndata_1 = loads(json_string)
\n\n\nConverts a json string into a python object made up of lists, dicts and strings.\n\nThe s in loads stands for string.\n\n\n\n"},{"id":"qHdp","level":3,"heading":"Json String - To JSON String","content":"
Json String - To JSON String
\n\n
from json import dumps\n\njson_string = dumps(data_1)
\n\n\nConverts data into a json string.\n\nThe s in dumps stands for string.\n\n\n\n"},{"id":"EYfB","level":3,"heading":"Json String - To Formatted JSON String","content":"
Json String - To Formatted JSON String
\n\n
from json import dumps\n\njson_string = dumps(data_1, indent = 4)
\n\n\nConverts data into a formatted json string.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"Qvg6","level":3,"heading":"Json File - From JSON File","content":"
Json File - From JSON File
\n\n
from json import load\n\nwith open(file_name,'r') as file:\n data_1 = load(file)
\n\nConverts a json file into a python object made up of lists, dicts and strings.\n\n\n\n"},{"id":"mc3t","level":3,"heading":"Json File - To JSON File","content":"
Json File - To JSON File
\n\n
from json import dump\n\nwith open(file_name, 'w') as file:\n\tdump(data_1, file)
from json import JSONEncoder\n\nclass ItemEncoder(JSONEncoder):\n\n def default(self, value):\n if type(value) is not ItemType:\n return super().default(value)\n\n return ...conver item to json...\n\n\njson.dump(data, cls = ItemEncoder)
\n\n\n\nTo create a custom json encoder, create a class inheriting from JSONEncoder and override the default() method.\n\n\n"},{"id":"eQzg","level":2,"heading":"Random","content":"
\n\nType: range\n\n\nRange is an immutable sequence of integers.\n\nThe integers start with min and end with the value before max_plus_1.\nmin defaults to 0.\nTechnically range is a class of immutable iterable objects.\nRange can be used anywhere a sequence can be used.\n\n\nExamples:\n\n
\n\nType: range\n\n\nThere is no built in range for float.\nUse the function declared here.\n\nReturns a range of float values from min to less than max.\n\n\nExamples:\n\n
def float_range(min, max = None, step = 1):\n if max is None:\n min, max = 0, min\n value = min\n while value < max:\n yield value\n value += step\n\nfor value in float_range(1.0, 3.0, 0.5):\n print(value)\n\n# Prints:\n#\n# 1.0\n# 1.5\n# 2.0\n# 2.5
from re import search\n\nmatch = search(match_pattern, string_to_search)\nmatch_text = match.group()
\n\n.search() Returns: re.Match | None\n.group() Returns: str\n\n\nReturns the first match in a string.\n\nReturns None if no match found.\n\n\nExample:\n\n
from re import search\n\nstring_1 = "123 abc 789"\nmatch = search(r"[a-zA-Z]+", string_1)\t\t# Find the letters in the string.\n\nletters_1 = match.group()\n# Returns "abc"\n\nletters_2 = string_1[match.start():match.end()]\n# Returns "abc"
from re import findall\n\nmatches = findall(match_pattern, string_to_search)
\n\nReturrns: list[str]\n\n\nReturns a list of all the matches.\n\n\nExample:\n\n
from re import findall\n\nstring_1 = "123 abc 456 def 789"\nmatches = findall(r"[a-zA-Z]+", string_1)\n\n# Returns ["abc", "def"]
\n\n\n\n"},{"id":"7t8E","level":3,"heading":"Regular Expressions - Match All","content":"
Regular Expressions - Match All
\n\n
= fullmatch(match_pattern, string_1)
\n\nUsage:\n\n
from re import fullmatch\n\n= fullmatch(match_pattern, string_1)\nmatch_text = match.group()
\n\n.fullmatch() Returns: re.Match | None\n.group() Returns: str\n\n\nReturns a match if the pattern matches the complete string.\n\n\nOtherwise returns None.\n\n\nExample:\n\n
from re import fullmatch\n\nstring_1 = "1234"\n\nmatch = fullmatch(r"\\d{4}", string_1)\n\nif match:\n\tprint ("got a match")\nelse:\n\tprint ("not a match")\n\nPrints: got a match
\n\n
from re import fullmatch\n\nstring_1 = "1234"\n\nmatch = fullmatch(r"\\d{3}", string_1)\n\nif match:\n\tprint ("got a match")\nelse:\n\tprint ("not a match")\n\nPrints: not a match
\n\n\n\n"},{"id":"pm3N","level":3,"heading":"Regular Expressions - Match Start","content":"
Regular Expressions - Match Start
\n\n
= match(match_pattern, string_1)
\n\nUsage:\n\n
from re import match\n\n= match(match_pattern, string_1)\nmatch_text = match.group()
\n\n.match() Returns: re.Match | None\n.group() Returns: str\n\n\nReturns a match if the string starts with the given pattern.\n\n\nReturns re.Match object if string_1 starts with match_pattern.\nOtherwise returns None.\n\n\nExample:\n\n
from re import match\n\nstring_1 = "123abc"\n\nmatch = match(r"\\d{3}", string_1)\n\nif match:\n\tprint ("got a match")\nelse:\n\tprint ("not a match")\n\nPrints: got a match
\n\nReturns: list[str]\n\n\nReturns a list of strings split on split_expression.\n\nsplit_expression is not returned in the results.\nStops after splitting split_count times if given.\n\n\nExample:\n\n
from re import split\n\nstring_1 = "ab12cd34ef"\nsplit_1 = split(r"\\d+", string_1)\n\n# Returns ['ab', 'cd', 'ef']
\n\n\n\n"},{"id":"dLYR","level":3,"heading":"Regular Expressions - Match Type","content":"
\n\n\n"},{"id":"asSX","level":3,"heading":"Regular Expressions - Match - To String","content":"
Regular Expressions - Match - To String
\n\n
= match_1.group()
\n\n\nReturns the matching text as a string.\n\n\n\n"},{"id":"W5vy","level":3,"heading":"Regular Expressions - Match - Start Position","content":"
Regular Expressions - Match - Start Position
\n\n
= match_1.start()
\n\n\nReturns the starting position of the matching text in the original string.\n\n\n"},{"id":"MFt5","level":3,"heading":"Regular Expressions - Match - End Position","content":"
Regular Expressions - Match - End Position
\n\n
= match_1.end()
\n\n\nReturns the starting position of the matching text in the original string.\n\n\n\n"},{"id":"ajLF","level":2,"heading":"Regular Expression Patterns","content":"
\n\nEscape\t\t\t\t\t\\\n\nEscape These\t\t\t\t ^ $ . * + ? - & | {} [] () \n\nAny Character\t\t\t.\n\nAlphanumeric, _\t\t\t\\w\t\t\t# A-Z, a-z, 0-9, _\t\t\t\nNon Alphanumeric, _\t\t\\W\nDigit\t\t\t\t\t\\d\t\t\t# 0-9\t\nNon Digit\t\t\t\t\\D\n\nWhitespace\t\t\t\t\\s\nNon Whitespace\t\t\t\\S\n\nStarts With\t\t\t\t\\A\nEnds With\t\t\t\t\\Z\nStarts or Ends With\t\t\\b\nDoesn't Start or Ends With\t\\B\n\nSet. Either a, b or c\t\t\t[abc]\nNot\t\t\t\t\t\t^a\nOr\t\t\t\t\t\ta|b\nFrom - To\t\t\t\ta-z\n\n0 or 1\t\t\t\t\t?\n0 or More\t\t\t\t*\n1 or More\t\t\t\t+\nn Times\t\t\t\t\t{n}\nm to n Times\t\t\t\t{m,n}\n\nMatch After\t\t\t\t(?<=after_this)match\nMatch Before\t\t\t\tmatch(?=before_this)\n\n\n\n"},{"id":"rYsV","level":3,"heading":"Regular Expressions - Pattern Reverse Lookup","content":"
Regular Expressions - Pattern Reverse Lookup
\n\n\\\t\tEscape\n\n.\t\tAny Character\n^\t\tStarts With\n$\t\tEnds With\n\n*\t\t0 or More Times\n+\t\t1 or More Times\n?\t\t0 or 1 Times\n{m}\t\tm Times\n{m,n}\tm to n Times\n\n^a\t\tNot\na|b\t\ta or b\na-z\t\ta to z\n\n[...]\tSet (One of These)\n(...)\tGroup\n\n\\A\t\tStart of String\n\\b\t\tBeginning or End of Word\n\\B\t\tNot Beginning or End of Word\n\\d\t\tDigit (0-9)\n\\D\t\tNon Digit (0-9)\n\\s\t\tWhitespace Character\n\\S\t\tNon Whitespace Character\n\\w\t\tWord Character (a-z, A-Z, 0-9, _)\n\\W\t\tNon Word Character\n\\Z\t\tEnd of String\n\n\n\n"},{"id":"7MTY","level":1,"heading":"Encode, Decode","content":"
Encode, Decode
\n\n\n\n"},{"id":"s1xk","level":2,"heading":"ASCII - Encode To ASCII","content":"
ASCII - Encode To ASCII
\n\n
= string_1.encode("ascii")
\n\nReturns: bytes\n\n\nConverts a string to an ASCII encoded byte array.\nNon ASCII characters will raise an exception.\n\n\n\n"},{"id":"MJPB","level":2,"heading":"ASCII - Decode From ASCII","content":"
ASCII - Decode From ASCII
\n\n
= bytes_1.decode("ascii")
\n\nRetuns: str\n\n\nConverts an ASCII encoded byte array to a string.\n\n\n\n"},{"id":"41x9","level":2,"heading":"UTF-8 - Encode To UTF-8","content":"
UTF-8 - Encode To UTF-8
\n\n
= string_1.encode("utf-8")
\n\nReturns: bytes\n\nConverts a string to an utf-8 encoded byte array.\n\n\n\n"},{"id":"AJz3","level":2,"heading":"UTF-8 - Decode From UTF-8","content":"
UTF-8 - Decode From UTF-8
\n\n
= bytes_1.decode("utf-8")
\n\nRetuns: str\n\nConverts a utf-8 encoded byte array to a string.\n\n\n\n"},{"id":"KeHx","level":2,"heading":"Hash - To MD5","content":"
Hash - To MD5
\n\nDo not use MD5\n(deprecated, vulnerabilities)\n\n
from hashlib import md5\n\n= md5(bytes_1)
\n\n\nReturns: _hashlib.HASH\n\n\nConverts a byte array into an MD5 hash.\n\n\nNote:\n\nMD5 is deprecated. Do not use.\nIt has major vulnerabilities that can be exploited.\n\nUse SHA2 instead.\n\n\n\n"},{"id":"yQUM","level":3,"heading":"Hash - To MD5 Digest","content":"
Hash - To MD5 Digest
\n\nDo not use MD5\n(deprecated, vulnerabilities)\n\n
from hashlib import md5\n\n= md5(bytes_1).digest()
\n\n\nReturns: bytes\n\n\nConverts a byte array into an MD5 digest.\n\n\n\n"},{"id":"Fy7V","level":3,"heading":"Hash - To MD5 Hex Digest","content":"
Hash - To MD5 Hex Digest
\n\nDo not use MD5\n(deprecated, vulnerabilities)\n\n
from hashlib import md5\n\n= md5(bytes_1).hexdigest()
\n\n\nReturns: str\n\n\nConverts a byte array into hex formatted MD5 digest.\n\n\n\n"},{"id":"DrFm","level":2,"heading":"Hash - To SHA256","content":"
Hash - To SHA256
\n\n
from hashlib import sha256\n\n= sha256(bytes_1)
\n\n\nReturns: _hashlib.HASH\n\n\nConverts a byte array into a SHA2 hash.\n\n\n\n"},{"id":"kgGG","level":3,"heading":"Hash - To SHA256 Digest","content":"
Hash - To SHA256 Digest
\n\n
from hashlib import sha256\n\n= sha256(bytes_1).digest()
\n\n\nReturns: bytes\n\n\nConverts a byte array into an SHA2 digest.\n\n\n\n"},{"id":"wrj3","level":3,"heading":"Hash - To SHA256 Hex Digest","content":"
Hash - To SHA256 Hex Digest
\n\n
from hashlib import sha256\n\n= sha256(bytes_1).hexdigest()
\n\n\nReturns: str\n\n\nConverts a byte array into an SHA2 digest in hex.\n\n\n\n"},{"id":"QX3X","level":1,"heading":"Files","content":"
from shutil import copytree\n\ncopytree(source, target)
\n\n\nCreates a copy of a directory..\n\n\n\n"},{"id":"Vn9S","level":3,"heading":"Directory - Create","content":"
Directory - Create
\n\n
mkdir(directory_name)
\n\nWith Import:\n\n
from os import mkdir\n\nmkdir(directory_path)
\n\n\nCreates a directory\nRaises FileExistsError if the directory exists.\n\n\n\n"},{"id":"uYR0","level":3,"heading":"Directory - Create Full Path","content":"
Directory - Create Full Path
\n\n
makedirs(directory_name)
\n\nWith Import:\n\n
from os import makedirs\n\nmakedirs(directory_path)
\n\nCreate, Ignore If Full Path Exists:\n\n
makedirs(directory_path, exist_ok = True)
\n\n\nCreates all the directories needed to form directory_path.\nBy default, will throw an error if full path already exists unless exist_ok = True.\n\n\n\n"},{"id":"gMT9","level":3,"heading":"Directory - Delete - Empty","content":"
Directory - Delete - Empty
\n\n
rmdir(directory_name)
\n\nWith Import:\n\n
from os import rmdir\n\nrmdir(directory_path)
\n\n\nDeletes empty directories only.\nRaises OSError if the directory is not empty.\n\n\n\n"},{"id":"s4Nj","level":3,"heading":"Directory - Delete - Non Empty","content":"
Directory - Delete - Non Empty
\n\n
rmtree(directory_name)
\n\nWith Import:\n\n
from shutil import rmtree\n\nrmtree(directory_path)
\n\n\nDeletes the directory and all its contents.\n\n\n\n"},{"id":"nvtf","level":3,"heading":"Directory - Delete All Files","content":"
Directory - Delete All Files
\n\n
for file in glob(join(directory_name, '*')):\n\tremove (file)
\n\nWith Imports:\n\n
from glob import glob\nfrom os import remove\nfrom os.path import join\n\nfiles = glob(join(directory_path, '*'))\nfor file in files:\n\tremove (file)
\n\n\nDeletes all the files in the directory.\n\nTo delete particular files, change '*' to match (e.g. '*.txt').\n\n\n\n"},{"id":"HTfk","level":3,"heading":"Directory - Exists? Is Directory?","content":"
Directory - Exists? Is Directory?
\n\n
= isdir(directory_name)
\n\nWith Import:\n\n
from os.path import isdir\n\nis_directory = isdir(directory_path)
\n\nReturns: bool\n\n\nReturns True if directory_path exists and is a directory.\nOtherwise, returns False.\n\n\n\n"},{"id":"0nM2","level":3,"heading":"Directory - Read","content":"
Directory - Read
\n\n
= listdir(directory_name)
\n\nWith Import:\n\n
from os import listdir\n\nfile_names = listdir(directory_path)
\n\nReturns: list of str\n\n\nReturns all files and directories for directory_path.\nReturns the file names only, not the full path.\n\n\n\n"},{"id":"mHaH","level":3,"heading":"Directory - Read, Directories Only","content":"
from os import listdir\nfrom os.path import isdir\nfrom os.path import join\n\ndirectories = filter(\n\t\tlambda file: isdir(join(directory_path, file)),\n\t\tlistdir(directory_path))
\n\nReturns: filter of str\n\n\nReturns list of all directory names in directory_path.\nReturns the file names only, not the path.\n\n\nExamples:\n\nDirectories in Current Directory:\n\n
from os import listdir\nfrom os.path import isdir\nfrom os.path import join\n\npath = '.'\n\ndirectories = filter(\n\t\tlambda file: isdir(join(path, file)),\n\t\tlistdir(path))\n\nprint(list(directories))
from os import listdir\nfrom os.path import isfile\nfrom os.path import join\n\nfile_names = filter(\n\t\tlambda file: isfile(join(directory_path, file)),\n\t\tlistdir(directory_path))
\n\nReturns: filter of str\n\n\nReturns list of file names.\nOnly returns the name, not the path.\n\n\nExamples:\n\nDirectories in Current Directory:\n\n
from os import listdir\nfrom os.path import isfile\nfrom os.path import join\n\npath = '.'\n\nfiles = filter(\n\t\tlambda file: isfile(join(path, file)),\n\t\tlistdir(path))\n\nprint(list(files))
from os import listdir\nfrom fnmatch import filter\n\nfile_names = filter(listdir(directory_path), file_filter)
\n\nReturns: list of str\n\n\nReturns list of matching file names only.\nReturns the file names only, not the path.\n\n\nExample:\n\n
from os import listdir\nfrom fnmatch import filter\n\nfile_names = filter(listdir("."), "*.txt")
\n\n\n\n"},{"id":"WYe6","level":3,"heading":"Directory - Read, Full Path","content":"
Directory - Read, Full Path
\n\n
= glob(join(directory_path, "*"))
\n\nWith Imports:\n\n
from glob import glob\nfrom os.path import join\n\nfile_paths = glob(join(directory_path, "*"))
\n\nReturns: list of str\n\n\nReturns all files and sbdirectories in directory_path.\nReturns the full path to the files.\n\n\n\n"},{"id":"tXEW","level":3,"heading":"Directory - Read, Full Path, Filtered","content":"
Directory - Read, Full Path, Filtered
\n\n
= glob(join(directory_name, "filter"))
\n\nWith Imports:\n\n
from glob import glob\nfrom os.path import join\n\nfile_paths = glob(join(directory_path, "filter"))
\n\nReturns: list of str\n\n\nReturns all files and sbdirectories in directory_path.\nReturns the full path to the files.\n\n\nExamples:\n\n
from glob import glob\nfrom os.path import join\n\nfile_paths = glob(join(directory_path, "*.txt"))
\n\n\n\n"},{"id":"pL31","level":3,"heading":"Directory - Read, Full Path, Recursive","content":"
\n\nReturns: list of str\n\n\nRecursively\nReturns full path to all files.\n\n\n\n"},{"id":"6H2v","level":3,"heading":"Directory - Read, Full Path, Recursive, Filtered","content":"
from os import walk\n\nfor root, directories, files in walk(directory_path):\n\t...
\n\nReturns:\n\n
root
str
\n
directories
list[str]
\n
files
list[str]
\n\n\nReturns the list of directories and files in each directory under and including directory_path).\nThe current directory is returned in root.\nWhen no files or directories are found, returns an empty list ([]).\n\n\nExample:\n\nWalk The Current Directory:\n\n
from os import walk\n\nfor root, directories, files in walk('.'):\n\n\tprint("Current Path:", root)\n\tprint("Directories:", directories)\n\tprint("Files:", files)\n\tprint()
\n\n\n\n"},{"id":"LADU","level":3,"heading":"File - Get Created Datetime","content":"
File - Get Created Datetime
\n\n
= datetime.fromtimestamp(getctime(file_name))
\n\nWith Import:\n\n
from datetime import datetime\nfrom os.path import getctime\n\ncreated_datetime_1 = datetime.fromtimestamp(getctime(full_path))
\n\nReturns: datetime\n\n\nReturns the file creation time as a datetime.\n\n\n\n"},{"id":"Eyf3","level":3,"heading":"File - Get Created Timestamp","content":"
File - Get Created Timestamp
\n\n
= getctime(file_name)
\n\nWith Import:\n\n
from os.path import getctime\n\ncreated_timestamp_1 = getctime(full_path))
\n\nReturns: float\n\n\nReturns the file creation time as a unix timestamp (epoch).\n\n\n\n"},{"id":"Kgsj","level":3,"heading":"File - Get Modified Datetime","content":"
File - Get Modified Datetime
\n\n
= datetime.fromtimestamp(getmtime(file_name))
\n\nWith Imports:\n\n
from os.path import getmtime\nfrom datetime import datetime\n\nmodified_datetime_1 = datetime.fromtimestamp(getmtime(full_path))
\n\nReturns: datetime\n\n\nReturns the file modification time as a datetime.\n\n\n\n"},{"id":"KhEn","level":3,"heading":"File - Get Modified Timestamp","content":"
File - Get Modified Timestamp
\n\n
= getmtime(file_name)
\n\nWith Import:\n\n
from os.path import getmtime\n\nmodified_timestamp_1 = getmtime(full_path)
\n\nReturns: float\n\n\nReturns the file modified time as a unix timestamp (epoch).\n\n\n\n"},{"id":"HJSc","level":3,"heading":"File - Get Size","content":"
File - Get Size
\n\n
= getsize(file_path)
\n\nWith Import:\n\n
from os.path import getsize\n\nfile_size = getsize(file_path)
\n\n\nReturns the size of a file.\n\n\n\n"},{"id":"W0qv","level":3,"heading":"File - Copy","content":"
File - Copy
\n\n
copyfile(source_path, destination_path)
\n\nWith Import:\n\n
from shutil import copyfile\n\ncopyfile(source_path, destination_path)
\n\n\nCreates a copy of a file.\n\nDoes not copy metadata.\n\n\n\n"},{"id":"gWXH","level":3,"heading":"File - Copy With Metadata","content":"
File - Copy With Metadata
\n\n
copy2(source_path, destination_path)
\n\nWith Import:\n\n
from shutil import copy2\n\ncopy2(source_path, destination_path)
\n\n\nCreates a copy of a file along with the metadata.\n\n\n\n"},{"id":"XC0h","level":3,"heading":"File - Delete","content":"
File - Delete
\n\n
remove(file_path)
\n\nWith Import:\n\n
from os import remove\n\nremove(file_path)
\n\n\nDeletes a file.\n\n\n\n"},{"id":"6X7x","level":3,"heading":"File - Exists?","content":"
File - Exists?
\n\n
= exists(file_name)
\n\nWith Import:\n\n
from os.path import exists\n\nfile_exists = exists(file_path)
\n\nReturns: bool\n\n\nReturns True if a file exists.\n\n\n\n"},{"id":"LcEP","level":3,"heading":"File - Is File?","content":"
File - Is File?
\n\n
= isfile(file_path)
\n\nWith Import:\n\n
from os.path import isfile\n\nis_file = isfile(file_path)
\n\nReturns bool\n\n\nReturns True if file_path exists and is a file (not a directory).\nOtherwise, returns False.\n\n\n\n"},{"id":"gkvT","level":3,"heading":"File - Join Paths","content":"
File - Join Paths
\n\n
= join(path_1, path_2...)
\n\nWith Import:\n\n
from os.path import join\n\njoined_path = join(path_1, path_2...)
\n\n\nReturns the paths joined together with the correct OS specific file separator.\n\n\n\n"},{"id":"XbZJ","level":3,"heading":"File - Move","content":"
File - Move
\n\n
rename(source_path, destination_path)
\n\nWith Import:\n\n
from os import rename\n\nrename(source_path, destination_path)
\n\n\nMoves a file to a location within the current drive only. \n\n\n\n"},{"id":"0xu6","level":3,"heading":"File - Move - Across Drives","content":"
File - Move - Across Drives
\n\n
move(source_path, destination_path)
\n\nWith Import:\n\n
from shutil import move\n\nmove(source_path, destination_path)
\n\n\nMoves a file within drive or copies it from one dirve to another.\nWhen copying across drives, he original is not deleted.\n\n\n\n"},{"id":"L3VM","level":3,"heading":"File - Rename","content":"
File - Rename
\n\n
rename(source_path, destination_path)
\n\nWith Import:\n\n
from os import rename\n\nrename(source_path, destination_path)
\n\n\nRenames a filename.\n\n\n\n"},{"id":"fafp","level":2,"heading":"File IO","content":"
\n\n\nThis will create a file with 0 bytes.\n\n\n"},{"id":"JyAK","level":3,"heading":"Binary File - Read","content":"
Binary File - Read
\n\n
with open(file_name,'rb') as file:\n\tcontents = file.read()
\n\nReturns: bytes\n\n\n\n"},{"id":"fXtg","level":3,"heading":"Binary File - Read By Byte","content":"
Binary File - Read By Byte
\n\n
with open(file_name, "rb") as file:\n\twhile (next_byte := file.read(1)):\n\t\t...
\n\nReads the file one byte at a time.\n\n\n\n"},{"id":"g39W","level":3,"heading":"Binary File - Write","content":"
Binary File - Write
\n\n
with open(file_name, 'wb') as file:\n\tfile.write(contents)
\n\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"6V0k","level":3,"heading":"Binary File - Append","content":"
Binary File - Append
\n\n
with open(file_name, 'ab') as file:\n\tfile.write(contents)
\n\nCreates a new file or appends to an existing one.\n\n\n\n"},{"id":"Apm9","level":3,"heading":"Text File - Read","content":"
Text File - Read
\n\n
with open(file_name,'r') as file:\n\tcontents = file.read()
\n\nReturns: str\n\n\n\n"},{"id":"77Jd","level":3,"heading":"Text File - Read By Character","content":"
Text File - Read By Character
\n\n
with open(file_name, 'r') as file:\n\n\tcharacters = []\n\twhile (next_character := file.read(1)):\n\t\tcharacters.append(next_character)
\n\nReturns: list of str\n\nReturns the contents of the file as a list in lines.\n\n\n\n"},{"id":"U4fN","level":3,"heading":"Text File - Read By Line","content":"
Text File - Read By Line
\n\n
with open(file_name, 'r') as file:\n\n\tlines = []\n\twhile (line := file.readline()):\n\t\tlines.append(line.rstrip('\\n'))
\n\nReturns: list of str\n\nReturns the contents of the file as a list in lines.\n\n\n\n"},{"id":"Semg","level":3,"heading":"Text File - Read All Lines","content":"
Text File - Read All Lines
\n\n
with open(file_name, 'r') as file:\n\tlines = file.readlines()
\n\nReturns: list of str\n\nReturns the contents of the file as a list in lines.\nThe lines include the newline characters.\n\n\n\n"},{"id":"UNPF","level":3,"heading":"Text File - Read All Lines, Stripped Newlines","content":"
Text File - Read All Lines, Stripped Newlines
\n\n
with open(file_name, 'r') as file:\n\tlines = [line.rstrip('\\n') for line in file]
\n\nReturns: list of str\n\nReturns the contents of the file as a list in lines.\nThe line's newline character is returned by default. rstrip, removes it.\n\n\n\n"},{"id":"Paqz","level":3,"heading":"Text File - Write","content":"
Text File - Write
\n\n
with open(file_name, 'w') as file:\n\tfile.write(contents)
\n\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"Wx2r","level":3,"heading":"Text File - Write Line","content":"
Text File - Write Line
\n\n
with open(file_name, 'w') as file:\n\tfile.write(line + '\\n')
\n\nWrites a single line to a file.\n\nYou have to add the newline character manually between lines.\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"dz0c","level":3,"heading":"Text File - Write Lines","content":"
Text File - Write Lines
\n\n
with open(file_name, 'w') as file:\n\t\tfile.write('\\n'.join(lines))
\n\nWrites a sequence of lines to a file.\n\nInserts a newline character between each line.\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"fF08","level":3,"heading":"Text File - Write Strings","content":"
Text File - Write Strings
\n\n
with open(file_name, 'w') as file:\n\t\tfile.writelines(strings)
\n\nWrites a sequence of strings to a file.\n\nwriteline() will NOT insert a newline character between each string.\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"Pas1","level":3,"heading":"Text File - Write","content":"
Text File - Write
\n\n
with open(file_name, 'w') as file:\n\tfile.write(contents)
\n\nDeletes the file if it exists before writing to it.\n\n\n\n"},{"id":"ByRG","level":3,"heading":"Text File - Append","content":"
Text File - Append
\n\n
with open(file_name, 'a') as file:\n\tfile.write(contents)
\n\nCreates a new file or appends to an existing one.\n\n\n\n"},{"id":"YWTT","level":3,"heading":"File - Seek","content":"
File - Seek
\n\n
file.seek(offset)
\n\n
file.seek(offset, whence)
\n\nPositions the read / write position within a file.\n\n\nwhence\t= 0\t\tAbsolute Position (Default)\n\t\t= 1\t\tRelative To Current Position\n\t\t= 2\t\tRelative To End of File\n\n\nExample:\n\n
with open(file_name, 'r+') as file:\n\tfile.seek(10)\n\tcontent = file.read(10)\n\tfile.seek(10)\n\tfile.write("**********")
\n\nReturns the OS specific form of the internal path separator...\nthe / or \\ in dir_1/file_1.\n\n\n\n"},{"id":"wTLv","level":3,"heading":"Path Separator - Paths Separator","content":"
Path Separator - Paths Separator
\n\n
import os\n\nseparator = os.pathsep
\n\nReturns the OS specific form of the paths separator...\nthe ; or : in dir_1;dir_2;dir_3\n\n\n\n"},{"id":"vTmz","level":1,"heading":"Standard Libraries","content":"
\n\n\nOverride the error() method.\n\nSubclass ArgumentParser and implement the error() method to override the error behavior.\nError messages will be sent to this method instead of calling sys.exit().\n\n\n\n"},{"id":"tskc","level":3,"heading":"Argparse - Parse","content":"
\n\n\nParses the command-line arguments.\n\nWill print help and exit if has '-h', '--help'.\nWill print errors and exit if any errors found.\n\n\n\n"},{"id":"KW64","level":4,"heading":"Argparse - Parse String","content":"
Argparse - Parse String
\n\n
= parser.parse_args(argument_list)
\n\nWill print help and exit if has '-h', '--help'.\nWill print errors and exit if any errors found.\n\n\n\n"},{"id":"qJMz","level":3,"heading":"Argparse - Flag Parameters","content":"
Argparse - Flag Parameters
\n\n\n\n"},{"id":"b0xn","level":4,"heading":"Argparse - Flag Parameter","content":"
parser.add_argument('--name', '-n',\n action = 'store_true',\n help = 'help text')
\n\n
if arguments.name:\n ...
\n\nReturns: bool\n\n\nDefines an argument flag.\n\nThe first add_argument parameter with leading '--' defines the field name.\nReturns True if present, False if not.\n\n\nExample:\n\n
\n\n\n\n"},{"id":"ecYf","level":4,"heading":"Argparse - Flag Parameter / As False","content":"
Argparse - Flag Parameter / As False
\n\n
parser.add_argument(..., action='store_false')
\n\nFull Usage:\n\n
parser.add_argument('-n', '--name',\n action = 'store_false',\n help = help text)
\n\n
if not arguments.name:\n ...
\n\nReturns: bool\n\n\nReturns False if present, True if not.\n\n\n\n"},{"id":"4QXj","level":4,"heading":"Argparse - Flag Parameter / As Value","content":"
\n\n\n\n"},{"id":"E0tM","level":4,"heading":"Argparse - Optional Argument / As Integer","content":"
Argparse - Optional Argument / As Integer
\n\n
parser.add_argument(..., type = int)
\n\nUsage:\n\n
parser.add_argument("-n", "--name",\n type = int,\n help = 'help text')
\n\n
= arguments.name
\n\nReturns: int\n\n\nDefines optional (named) argument.\n\nReturns the value as an integer if present, or None if missing.\n\n\n\n"},{"id":"btZM","level":4,"heading":"Argparse - Optional Argument / Choice From List","content":"
\n\n\nDefines optional (named) argument of limited choices.\n\nWill report an error if an invalid value is given.\n\n\n\n"},{"id":"CwDx","level":4,"heading":"Argparse - Optional Argument / Append Value","content":"
group = parser.add_mutually_exclusive_group()\n\ngroup.add_argument('option_1', ...)\ngroup.add_argument('option_2', ...)
\n\n\nDefines a group of mutually exclusive arguments.\n\nOnly one of the defined arguments can exist.\n\n\n\n"},{"id":"cswg","level":3,"heading":"Argparse - Arguments","content":"
Argparse - Arguments
\n\n\n\n"},{"id":"n7Ld","level":4,"heading":"Argparse Argument - As Integer","content":"
Argparse Argument - As Integer
\n\n
parser.add_argument(..., type = int)
\n\nReturns: int\n\n\nReturns the argument as an integer\n\n\n\n"},{"id":"qdA2","level":4,"heading":"Argparse Argument - As Return Type","content":"
Argparse Argument - As Return Type
\n\n
parser.add_argument(..., type = return_type)
\n\n\nCasts the return value to the given type before returning.\n\n\nReturn Types:\n\n
int\nfloat\nascii\nord\nopen
\n\n\n\n"},{"id":"49zA","level":4,"heading":"Argparse Argument - Choice from List","content":"
\n\nReturns: str\n\n\nReturns one of the integers in choices.\nWill report an error if an invalid value is given.\n\n\n\n"},{"id":"8V8b","level":4,"heading":"Argparse Argument - Choice from Integers","content":"
\n\nType: int\n\n\nReturns the argument as a choice of integers.\n\nReturns one of the integers in choices.\nWill report an error if an invalid value is given.\n\n\n\n"},{"id":"EtC5","level":4,"heading":"Argparse Argument - 0 or 1 (Optional Value)","content":"
\n\nReturns: str\n\nReturns an optional value.\n\nApplies to positional and named parameters.\n\n\n\n"},{"id":"KdUr","level":4,"heading":"Argparse Argument - 0 or More Values","content":"
\n\nReturns: list\n\n\nReturns 0 or more values.\n\nApplies to positional and named parameters.\n\n\n\n"},{"id":"ytgu","level":4,"heading":"Argparse Argument - 1 or More Values","content":"
\n\nReturn: list\n\n\nReturns a list of values.\n\nThrows an error if none found.\nApplies to positional and named parameters.\n\n\n\n"},{"id":"PHYM","level":4,"heading":"Argparse Argument - N Values","content":"
\n\nReturns: list\n\n\nReturns a list of n values.\n\nApplies to positional and named parameters.\n\n\n\n"},{"id":"Pbxe","level":3,"heading":"Argparse Help","content":"
Argparse Help
\n\n\n\n"},{"id":"nVuH","level":4,"heading":"Argparse Help - Add Help Flag","content":"
Argparse Help - Add Help Flag
\n\nIncluded by default.\n\nHelp argument flags:\n\n
app_name -h\napp_name --help
\n\n\n\n"},{"id":"KRj7","level":4,"heading":"Argparse Help - Disable Default Help","content":"
Argparse Help - Disable Default Help
\n\n
parser = ArgumentParser(..., add_help = False)
\n\n\nDisables the default help options.\n\n\n\n"},{"id":"DsFW","level":4,"heading":"Argparse Help - Set Program Name","content":"
\n\n\nSets the default value when the argument doesn't exist.\n\nBy default, argparse returns None.\n\n\n"},{"id":"Gf8K","level":4,"heading":"Argparse Argument - Custom Field Name","content":"
\n\n\nExplicitly defines the field name the argument value will be stored in.\n\n\n\n"},{"id":"NPC0","level":4,"heading":"Argparse Settings - Disable Exit On Error","content":"
from argparse import ArgumentParser, ArgumentError\n\nparser = ArgumentParser(..., exit_on_error = False)\n\ntry:\n arguments = parser.parse_args()\n ...\nexcept ArgumentError as error:\n ...
\n\nDefault: True\n\n\nThrows ArgumentError instead of exiting the application.\n\n\n\n"},{"id":"dtRv","level":4,"heading":"Argparse Argument - Make Require","content":"
Argparse Argument - Make Require
\n\n
parser.add_argument(..., required = True)
\n\n\nRequires the argument to be present.\n\nWill display help and exit if not found.\n\n\n\n"},{"id":"f1ty","level":2,"heading":"ConfigParser","content":"
ConfigParser
\n\nReads, and writes Windows style ini files.\n\n\n\n"},{"id":"Z4BP","level":3,"heading":"ConfigParser - Video Tutorial","content":"
ConfigParser - Video Tutorial
\n\nGet going faster with our 5 minute tutorial here:\n\n
from configparser import ConfigParser\n\ndef read_sectionless(file_name):\n\n\twith open(file_name,'r') as file:\n\t\tcontents = file.read()\n\n\tconfig = ConfigParser()\n\tconfig.read_string(f'[default]\n{contents}')\n\treturn config['default']
\n\nRead File:\n\n
config_1 = read_sectionless(file_name)
\n\nGet Value:\n\n
property_1 = config_1.get('property-1')
\n\n\n\nReturns all properties defined before any [section] in the config file.\nAll sections and their properties are ignored.\n\n\n\n"},{"id":"dzUJ","level":4,"heading":"ConfigParser - Read From String","content":"
ConfigParser - Read From String
\n\n
from configparser import ConfigParser\n\nconfig_parser = ConfigParser()\nconfig_parser.read_string(string_representation)
\n\n\nReads a string as if it were an ini file.\nUseful for unit testing.\n\n\n\n"},{"id":"ZDyc","level":4,"heading":"ConfigParser - Write File","content":"
ConfigParser - Write File
\n\n
with open(file_name, 'w') as file:\n\tconfig_parser.write(file)
\n\n\nSection section_name must exist.\n'value' must be a string.\n\n\n\n"},{"id":"24NL","level":4,"heading":"ConfigParser Property - Exists?","content":"
\n\n\nReturns: str\n\n\n#1 - Raises configparser.NoSectionError if section not found.\n#1 - Raises configparser.NoOptionError if property not found.\n\n#2 - Raises NameError if section or property not found.\n\n\n\n"},{"id":"KqYd","level":4,"heading":"ConfigParser Property - Get or Default","content":"
\n\n\nReturns: str\n\n\nReturns fallback_value if property not found.\n\n\n\n"},{"id":"fC74","level":4,"heading":"ConfigParser Property - Get As Boolean","content":"
\n\n\nReturns: int\n\n\n\nRaises InvalidValue if not an integer.\n\n\n\n"},{"id":"cTxr","level":4,"heading":"ConfigParser Property - Get As Float","content":"
\n\n\nReturns: float\n\n\n\nRaises InvalidValue if not a float.\n\n\n\n"},{"id":"1zN7","level":3,"heading":"ConfigParser Section","content":"
ConfigParser Section
\n\nThe ConfigParser section is a subclass of MutableMapping (collections.abc.MutableMap).\n\n\n\n"},{"id":"7K6j","level":4,"heading":"ConfigParser Section - Add","content":"
\n\n\nRaises NameError if section not found.\n\n\n\n"},{"id":"dfT4","level":4,"heading":"ConfigParser Sections - Get All Section Names","content":"
ConfigParser Sections - Get All Section Names
\n\n
= config_parser.sections()
\n\n\nReturns: list of str\n\n\nReturns a list of section names.\n\n\n\n"},{"id":"Kvz1","level":3,"heading":"ConfigParser Section Properties","content":"
\n\n\n#1 - Returns None if not found.\n\n#2 - Raises KeyError if not found.\n\n\n\n"},{"id":"4H1s","level":4,"heading":"ConfigParser Section Property - Get As Boolean","content":"
ConfigParser Section Property - Get As Boolean
\n\n
= section_1.getbool('property_name')
\n\n\nReturns: bool\n\n\n\nRaises InvalidValue if not a boolean value.\nNot case sensitive.\n\n\nTrue Values:\n\n
true | yes | on | 1
\n\nFalse Values:\n\n
false | no | off | 0
\n\n\n\n"},{"id":"GHY3","level":4,"heading":"ConfigParser Section Property - Get As Integer","content":"
ConfigParser Section Property - Get As Integer
\n\n
= section_1.getint('property_name')
\n\n\nReturns: int\n\n\n\nRaises InvalidValue if not an integer.\n\n\n\n"},{"id":"81Mg","level":4,"heading":"ConfigParser Section Property - Get As Float","content":"
ConfigParser Section Property - Get As Float
\n\n
= section_1.getfloat('property_name')
\n\n\nReturns: float\n\n\n\nRaises InvalidValue if not a float.\n\n\n\n"},{"id":"7Z2T","level":4,"heading":"ConfigParser Section Properties - Get All Names","content":"
ConfigParser Section Properties - Get All Names
\n\n
= config_parser.options(section_name)
\n\nor\n\n
= list(section_1.keys())
\n\n\nReturns: list of str\n\n\nReturns a list of all the property names for that section.\n\n\n\n"},{"id":"ztTt","level":3,"heading":"ConfigParser - Iterate Over Values","content":"
ConfigParser - Iterate Over Values
\n\n
for section_name in config_1.sections():\n\n\tsection = config_1[section_name]\n\n\tfor property_name, value in section.items():\n\t\tprint(section_name, property_name, ":", value)
\n\n\nIterates over each section and displays all the properties and their values.\n\n\n\n"},{"id":"N1Gu","level":3,"heading":"Ini File - Sample File","content":"
Ini File - Sample File
\n\n
# Comment line\n\n[section-1]\nproperty-1 = value 1\nproperty-2 = value 2\n\n[section-2]\nproperty-3 = value 3\n\n[types]\nbool-true-1 = yes\nbool-true-2 = true\nbool-true-3 = 1\nbool-false = no\n\nint-1 = 42\nfloat-1 = 12.001
from urllib.request import urlopen\nfrom urllib.error import HTTPError\nfrom urllib.error import URLError\n\ntry:\n\n\twith urlopen(url) as response:\n\t\tcontent = response.read()\n\t...\n\nexcept URLError as error:\n\n\t# Unable to make request...\n\n\tmessage = error.reason\n\nexcept HTTPError as error:\n\n\t# Server returned error...\n\n\tstatus_code = error.code\n\tmessage = error.reason\n\theaders = error.headers
\n\nConverts an object hierarchy into a byte stream so it can be saved and then restored later.\n\nUnpickling is the inverse operation converting a byte stream back into the object hierarchy.\n\n\n\n"},{"id":"zJMy","level":3,"heading":"Pickle - Pickle","content":"
\n\n\n#1 - Pass arguments with the command in a single list.\n\n\nExample:\n\n
from subprocess import run\n\nrun(['ls', '-1'])
\n\n\n\n"},{"id":"zQYS","level":2,"heading":"Execute Command - Run Shell Command","content":"
Execute Command - Run Shell Command
\n\n
from subprocess import run\n\nrun(command, shell = True)
\n\n\nStarts the shell and executes command on it.\nAllows the script to run shell only commands (e.g. echo).\ncommand is a string with the complete command, arguments included.\n\n\nExample:\n\n
from subprocess import run\n\nrun('echo "This is how to run a shell command."', shell=True)
\n\n\n\n"},{"id":"pHEs","level":2,"heading":"Execute Command - Get Exit Code","content":"
Execute Command - Get Exit Code
\n\n
from subprocess import run\n\nresults = run(command)\nexit_code = results.returncode
\n\nReturns: int\n\n\nGets the exit code returned by the process after it completed.\n\n\n\n\n"},{"id":"CZVQ","level":2,"heading":"Execute Command - Get Standard Output","content":"
from unittest import TestCase\n\nclass TestMyStuff(TestCase):\n\n\tdef setUp(self):\t\t\t\t\t# Run Before Every Test\n\t\t...\n\n\tdef tearDown(self):\t\t\t\t\t# Run After Every Test\n\t\t...\n\n\tdef test_this_function(self)\t\t# Name Must Start With test\n\t\t...
from unittest import TestCase\n\nclass TestClass1(TestCase):\n\n\tdef test_function_1(self):\n\t\t...
\n\n\nDefines a test class.\n\nAll test functions must start with test_.\n\n\n\n"},{"id":"BY94","level":3,"heading":"Test - Define - Function","content":"
Test - Define - Function
\n\n
def test_function_1(self):
\n\nUsage:\n\n
from unittest import TestCase\n\nclass TestClass1(TestCase):\n\n\tdef test_function_1(self):\n\t\t...
\n\n\nDefines a test function.\n\nTest functions must start with test_.\n\n\n\n"},{"id":"63gN","level":3,"heading":"Test - Define - Setup","content":"
Test - Define - Setup
\n\n
class TestClass1(TestCase):\n\n\tdef setUp(self):\n\t\t...
\n\nSets up the test environment before each test.\n\nAdd whatever data is needed to the class instance.\nRuns before every test.\n\n\n\n"},{"id":"hrjz","level":3,"heading":"Test - Define - Teardown","content":"
Test - Define - Teardown
\n\n
class TestClass1(TestCase):\n\n\tdef tearDown(self):\n\t\t...
\n\nTears down the test environment after each test is run.\n\nRuns after every test.\nRuns even if test fails.\n\n\n\n"},{"id":"2zT3","level":3,"heading":"Test - Define - Unit Test","content":"
Test - Define - Unit Test
\n\n
class TestClass1(TestCase):\n\n\tdef test_unit_test_name(self):\n\t\t...
\n\nMethod names must start with 'test'.\n\n\n\n"},{"id":"wdjY","level":2,"heading":"Test Assertions","content":"
\n\nCalls the method to be tested (function_1).\nFails if the exception ExceptionType is not raised.\n\n\n\n"},{"id":"Nxhr","level":3,"heading":"Test Assertion - Fail","content":"
Test Assertion - Fail
\n\n
self.fail()
\n\nFails test immediately.\n\n\n\n"},{"id":"mYPg","level":3,"heading":"Test Assertion - Attribute Exists","content":"
Test Assertion - Attribute Exists
\n\n
self.assertTrue(\n\thasattr(obj, intendedAttr),\n\tmsg=f'obj lacking an attribute. {obj=}, {intendedAttr=}')
from os import getcwd\nfrom os.path import join\nfrom sys import path\n\nPROJECT_PATH = getcwd()\npath.append (join (PROJECT_PATH, "src"))
\n\n\nDefines the project source directory for tests to use.\n\nCreate __init__.py in tests folder and add the code.\nIf the source folder is other than src, change src (above) to match.\nRun tests from the project root directory.\n\n\n\n"},{"id":"EVAz","level":1,"heading":"doctest","content":"
doctest
\n\nA doctest is one or more tests written into the docstring.\nThey follow the format of python cli commands followed by their output.\n\n\nOfficial Docs: \nhttps://docs.python.org/3/library/doctest.html\n\n\n\n"},{"id":"q7MX","level":2,"heading":"doctest - Basics","content":"
doctest - Basics
\n\nDefine:\n\n
def square(x):\n """ squares a number\n\n >>> square(2)\n 4\n \n """\n\n return x ** 2
\n\nEnable:\n\n
if __name__ == "__main__":\n import doctest\n doctest.testmod()
from typing import Tuple\n\ntuple_1: Tuple[type_1, type_2, ...]
\n\n\n\n"},{"id":"s7Hb","level":2,"heading":"Type Hints - Union Type","content":"
Type Hints - Union Type
\n\n
union_1: str | float
\n\n\nDefines the type hint for a value that may be one of two or more types.\n\n\n\n"},{"id":"PR5z","level":2,"heading":"Type Hints - Union Type (Alternative)","content":"
Type Hints - Union Type (Alternative)
\n\n
union_1: Union[str, float]
\n\nUsage:\n\n
from typing import Union\n\ntuple_1: Union[type_1, type_2, ...]
\n\n\nDefines the type hint for a value that may be one of two or more types.\n\n\n\n"},{"id":"y6s1","level":2,"heading":"Type Hints - Variable Type","content":"
Type Hints - Variable Type
\n\n
name: type
\n\n\nDefines the type of a variable.\nThe type is not compiler enforced.\n\n\nBasic Types:\n\n
\n\nUse the venv package to create a local python environment separate from the system environmnent.\n\nThis will allow your application to load and run it's own libraries in it's own version of python.\n\n\n\n"},{"id":"2mGX","level":2,"heading":"Virtual Environment - Create","content":"
Virtual Environment - Create
\n\n
python3 -m venv venv_directory
\n\nCreates a virtual environment in the directory venv_directory.\n\n\nTypical Example:\n\n
\n\nStarts the venv and then runs the module in that environment.\n\nRun from the project root directory.\nRun this bash script from the command-line.\n\n\nTypical Example:\n\nBash:\n\n
\n\nRun deactivate to exit the venv environment.\n\n\n\n"},{"id":"SgBZ","level":2,"heading":"Virtual Environment Variable","content":"
Virtual Environment Variable
\n\n
VIRTUAL_ENV
\n\nContains the path to the parent of the virtual environment bin directory.\n\n\n\n"},{"id":"RJeQ","level":1,"heading":"Environment Variables","content":"
\n\n#1 - Raises KeyError if not found.\n\n#2 - Returns None if not found.\n\n\nReads the value of the environment variable.\n\n\nEquivalent To:\n\n
= os.getenv(name)
\n\n\nExample:\n\n
from os import environ\n\nprint (environ['PYTHONPATH'])
\n\n\n\n"},{"id":"VpTC","level":2,"heading":"Environment Variable - Get All","content":"
Environment Variable - Get All
\n\n
from os import environ\n\n= environ.keys()
\n\n\nExample:\n\n
from os import environ\n\nfor key in sorted(environ.keys(), key = str.lower):\n\tprint(f'{key:<24} {environ[key]}')\n\nprint(f'{"Count":<24} {len(environ.keys())}')
\n\nThe smallest sequence of instructions that can be managed by the OS.\n\nGreat for IO bound operations.\nDo not use for CPU bound operations.\n\n\nEach Thread Has:\n\n\tRegisters\n\tStack\n\nThreads Share:\n\n\tCommon Memory\n\tResources\n\nLocal Variables\n\n\tStored on thread's stack\n\nThread Synchronization\n\n\tUse Lock\n\tUse Semaphore\n\tUse Queue\n\n\n\n"},{"id":"zw3N","level":3,"heading":"Thread - Basics","content":"
class ThreadClass(Thread):\t\t#1\n\n\tdef __init__(self):\n\t\tThread.__init__()\n\n\tdef run(self):\t\t\t\t#2\n\t\t...
\n\nCreate:\n\n
thread_1 = ThreadClass()
\n\n\n#1 - Inherit from Thread\n\n#2 - Override run()\n\n\n\n"},{"id":"tNWj","level":4,"heading":"Thread - Create Thread Class - With Arguments","content":"
Thread - Create Thread Class - With Arguments
\n\n
from threading import Thread
\n\nDefine:\n\n
class WorkerClass(Thread):\n\n\tdef __init__(self, argument_1, ...):\n\t\tThread.__init__(self)\t\t#1\n\t\t...
\n\nStart:\n\n
worker_1 = WorkerClass(argument_1, ...)
\n\n\n#1 - Must call Thread.__init__()\n#1 - Must Be First Line In __init__ Method\n\n\n\n"},{"id":"XBnR","level":3,"heading":"Thread - Operations","content":"
\n\n\nStarts the execution of the thread.\nThe thread is initially stopped.\n\n\n\n"},{"id":"rZaQ","level":4,"heading":"Thread - Stop On Application Exit","content":"
Thread - Stop On Application Exit
\n\n
thread_1.daemon = True
\n\n\nStops execution when the parent or main thread terminate.\nMust be called before calling .start().\n\n\n\n"},{"id":"eAVL","level":4,"heading":"Thread - Wait For Completion","content":"
Thread - Wait For Completion
\n\n
thread_1.join()
\n\nBlocks the current thread until thread_1 completes.\n\n\n\n"},{"id":"zT9V","level":4,"heading":"Thread - Is Alive?","content":"
Thread - Is Alive?
\n\n
= thread_1.is_alive()
\n\nIs alive means it is actively running.\nFalse when either not started or is terminated.\n\n\n\n"},{"id":"UkHV","level":4,"heading":"Thread - Is Terminated?","content":"
Thread - Is Terminated?
\n\n
= not thread_1.is_alive()
\n\nWill be True after the thread terminates.\nMust call .start() first.\n\n\n\n"},{"id":"MPpD","level":2,"heading":"Process","content":"
Process
\n\nA running instance of a program.\n\nIt has:\n\n\tSystem Resources\n\tAssigned Memory Space\n\tSecurity Attributes\n\tProcess State\n\nEach Process Has:\n\n\tIt's Own GIL\n\tSelf Contained Memory\n\nProcesses can be paused or terminated.\n\nProcesses have a big memory footprint.\nContext switch between processes is expensive.\n\n\n"},{"id":"fZ5j","level":3,"heading":"Process - Basics","content":"
\n\n\n\n"},{"id":"vw5V","level":4,"heading":"Process - Create Process Class","content":"
Process - Create Process Class
\n\n
from processing import Process
\n\nDefine: \n\n
class ProcessClass(Process):\t#1\n\n\tdef run(self):\t\t\t\t#2\n\t\t...
\n\nCreate:\n\n
process_1 = ProcessClass()
\n\n\n#1 - Inherit from Process\n\n#2 - Override run()\n\n\n\n"},{"id":"Pqua","level":4,"heading":"Process - Create Process Class - With Arguments","content":"
Process - Create Process Class - With Arguments
\n\n
from processing import Process
\n\nDefine:\n\n
class WorkerClass(Process):\n\n\tdef __init__(self, argument_1, ...):\n\t\tProcess.__init__(self)\t\t\t#1\n\t\t...
\n\nStart:\n\n
worker_1 = WorkerClass(argument_1, ...)
\n\n\n#1 - Must call Process.__init__()\n#1 - Must Be First Line In __init__ Method\n\n\n\n"},{"id":"A8hH","level":3,"heading":"Process - Operations","content":"
\n\n\nStarts the execution of the process.\nThe process is initially stopped.\n\n\n\n"},{"id":"9Gne","level":4,"heading":"Process - Stop on Application Exit","content":"
Process - Stop on Application Exit
\n\n
process_1.daemon = True
\n\n\nStops execution when the parent or main process terminate.\nMust be called before calling .start().\n\n\n"},{"id":"Awen","level":4,"heading":"Process - Terminate","content":"
Process - Terminate
\n\n
process_1.terminate()
\n\nMay cause issues such as putting the system into an inconsistent state.\nWill not run any finally clauses or exit handlers. Its Dead!\n\nPrefer something like a poison pill.\n\n\n\n"},{"id":"EZhy","level":4,"heading":"Process - Wait For Completion","content":"
Process - Wait For Completion
\n\n
process_1.join()
\n\nBlocks the current process until process_1 completes.\n\n\n\n"},{"id":"ffTz","level":4,"heading":"Process - Get Exit Code","content":"
Process - Get Exit Code
\n\n
= process_1.exitcode
\n\nValues:\n\n\t0 - No Error\n\t1 - Error\n\t< 0 - Terminated.\n\t\t\tTerminating Signal code = .exitcode * -1\n\n\n\n"},{"id":"Scqv","level":4,"heading":"Process - Is Alive?","content":"
Process - Is Alive?
\n\n
= process_1.is_alive()
\n\nIs alive means it is actively running.\nFalse when either not started or is terminated.\n\n\n\n"},{"id":"88KQ","level":4,"heading":"Process - Is Terminated?","content":"
Process - Is Terminated?
\n\n
= not process_1.is_alive()
\n\nWill be True after the process terminates.\nMust call .start() first.\n\n\n\n"},{"id":"nA08","level":2,"heading":"Process Pool","content":"
\n\n\nBy default processes live as long as the pool is alive.\nNote the initial arguments do not need to be picklable!\n\n\n\n"},{"id":"MY3m","level":3,"heading":"Pool - Operations","content":"
\n\n\nReturns: Result\n\n\nPerforms worker_function on args.\napply() blocks until the worker function is done.\n\n\n\n"},{"id":"uQfU","level":4,"heading":"Pool - Perform Single Operation Asynchronously","content":"
\n\n\nReturns: AsyncResult\n\n\napply_async() does not block.\n\n\n\n"},{"id":"fs8Z","level":4,"heading":"Pool - Get Single Async Result","content":"
Pool - Get Single Async Result
\n\n
= async_result.get()
\n\n
= async_result.get(timeout_seconds)
\n\n\nReturns: The Actual Result\n\n\n.get() blocks until all processes are finished.\n\n\n\n"},{"id":"gMZa","level":4,"heading":"Pool - Perform Multiple Operations","content":"
\n\n\nPerforms worker_function on all poll processes\nThis call blocks until all results are in.\nworker_function should take a single parameter which will be given from list_of_arguments.\n\n\n\n"},{"id":"H9YY","level":4,"heading":"Pool - Perform Multiple Operations Asynchronously","content":"
\n\n\nReturns: AsyncResult\n\n\nmap_async() does not block.\n\n\n\n#### Pool - Get Map Async Results\n\n
= async_result.get()
\n\n
= async_result.get(timeout_seconds)
\n\n\nReturns: List of Actual Results\n\n\n.get() blocks until all processes are finished.\n\n\n\n"},{"id":"tKmB","level":4,"heading":"Pool - Terminate","content":"
\n\n\nBlocks until all pool worker processes exit.\nCan only be called after .close() or .terminate()\n\n\n\n"},{"id":"BA0x","level":2,"heading":"Pool Executor","content":"
\n\n\nReturns: concurrent.futures.Future\n\n\nSubmits a single task.\nsubmit() does not block.\n\nFor ProcessPoolExecutor, make sure the worker function and arguments are pickleable!\n\n\n\n"},{"id":"PDzf","level":4,"heading":"Executor - Submit Task Map","content":"
\n\n\nReturns: result_iterator (an iterator)\n\n\nSubmit multiple requests to the task.\nmap() does not block.\n\nFor ProcessPoolExecutor, make sure the worker function and arguments are pickleable!\n\n\n\n"},{"id":"FuGU","level":4,"heading":"Executor - Shutdown","content":"
\nAn object that is a proxy for a future result that has yet to be computed.\n\n
concurrent.futures.Future
\n\nFutures can raise exceptions.\n\n\n\n"},{"id":"PngD","level":3,"heading":"Future - Cancel","content":"
Future - Cancel
\n\n
= future_1.cancel()
\n\n\nReturns: bool\n\n\nAttempts to cancel a request.\nReturns True if successful.\n\n\n\n"},{"id":"SNu3","level":3,"heading":"Future - Is Complete?","content":"
Future - Is Complete?
\n\n
= future_1.done()
\n\n\n\n"},{"id":"pL7u","level":3,"heading":"Future - Get Value","content":"
Future - Get Value
\n\n
= future_1.result()
\n\n\nresult() blocks until the result is available.\n\n\n\n"},{"id":"UqaB","level":3,"heading":"Future - Get With Exception Handling","content":"
Future - Get With Exception Handling
\n\n
try:\n\tresult = future_1.result()\nexcept Exception as exception:\n\t...
\n\n\nExceptions are returned through the future itself.\n\n\n\n"},{"id":"3pC0","level":3,"heading":"Future - Get Exception","content":"
Future - Get Exception
\n\n
= future_1.exception()
\n\n
= future_1.exception(timeout = timeout_seconds)
\n\nexception() blocks until a result is available unless a timeout is specified.\n\n\n\n"},{"id":"q5ku","level":3,"heading":"Future - Add Callback Function","content":"
Future - Add Callback Function
\n\n
= future_1.add_done_callback(callback_function)
\n\n\nExceptions are not returned the the callback function.\n\n\n\n"},{"id":"Z99x","level":3,"heading":"Futures - Wait Until All Complete","content":"
Futures - Wait Until All Complete
\n\n
from concurrent.futures import wait\nfrom concurrent.futures import ALL_COMPLETE
\n\nfutures is a list of futures to wait for.\nBlocks until all futures are complete.\n\n\n\n"},{"id":"BY9K","level":3,"heading":"Futures - Wait Until First Complete","content":"
Futures - Wait Until First Complete
\n\n
from concurrent.futures import wait\nfrom concurrent.futures import FIRST_COMPLETE
\n\n\nfutures is a list of futures to wait for.\nBlocks until the first future completes.\n\n\n\n"},{"id":"AMuM","level":3,"heading":"Futures - Process As Completed","content":"
\n\nPipes allow communication between processes.\nPipes are bidirectional by default.\nContains no locks and no guarantees.\nIf two processes write to the same side of the queue, data can get corrupt.\n\n\n\n"},{"id":"qMyu","level":3,"heading":"Pipe - Create","content":"
\n\n\nPass connection_1, connection_2 to the target processes.\nEnsure each process should send on one connection and receive on the other.\n\nExample:\n\n\tProcess 1 should send on connection_1, and receive on connection_2.\n\tProcess 2 should send on connection_2, and receive on connection_1.\n\n\n\n"},{"id":"yE7r","level":4,"heading":"Pipe - Create - Unidirectional","content":"
Pipe - Create - Unidirectional
\n\n
from multiprocessing import Pipe
\n\n
connection_receive, connection_send = Pipe(False)
\n\n\nPass connection_receive, connection_send to the target processes.\n\n\n\n"},{"id":"zx1k","level":3,"heading":"Pipe - Operations","content":"
\n\n\nGet next item.\n\n\n#1 - If no items, waits until one becomes available.\n\n#2 - If no items, raises QueueEmpty.\n\n\n\n"},{"id":"wgYt","level":4,"heading":"Queue - Is Empty?","content":"
Queue - Is Empty?
\n\n
= queue_1.empty()
\n\nReturns: bool\n\nReturns True if empty.\n\n\n\n"},{"id":"bJa1","level":4,"heading":"Queue - Is Full?","content":"
Queue - Is Full?
\n\n
= queue_1.full()
\n\nReturns: bool\n\nReturns True if the queue is full and can't take any more items.\n\n\n\n"},{"id":"uAJG","level":4,"heading":"Queue - Maximum Size","content":"
Queue - Maximum Size
\n\n
= queue_1.maxsize
\n\n\nReturns the maximum allowed size of the queue.\nReturns 0 if no maximum set.\n\n\n\n"},{"id":"qCsV","level":4,"heading":"Queue - Size","content":"
Queue - Size
\n\n
= queue_1.qsize()
\n\nReturns the number of items in the queue.\n\n\n\n"},{"id":"b2u4","level":4,"heading":"Queue - Wait Until Empty","content":"
Queue - Wait Until Empty
\n\n
queue_1.join()
\n\n\nBlocks until the queue is empty.\n\n\n\n"},{"id":"Gdvh","level":4,"heading":"Queue - Wait Until Task Complete","content":"
Queue - Wait Until Task Complete
\n\n
queue_1.task_done()
\n\n\nBlocks until the queue is empty.\nFor thread queues only.\n\n\n\n"},{"id":"Mb1k","level":2,"heading":"Event","content":"
Event
\n\nPrefer Queues\n\nEvent is basically a listener that notifies other classes when a single event has occurred.\nThe server sets or notifies the go condition by setting .set().\n\nListeners will block while event is False.\nListeners will go when the event is True.\n\n\n\n"},{"id":"kv8Z","level":3,"heading":"Event - Basics","content":"
\n\n\tLocked\n\tUnlocked\n\n\n\n"},{"id":"QyQG","level":3,"heading":"Lock - When Not Needed","content":"
Lock - When Not Needed
\n\nFor atomic operations...\n\n\tAssigning a simple value\n\tGetting a dictionary or list item.\n\tAdding an item to a dictionary or list.\n\n\n\n"},{"id":"hVrj","level":3,"heading":"Lock - Basics","content":"
\n\n\nAllows a thread to call acquire on a lock they have already acquired.\nWith Lock this would block and the thread would be deadlocked.\n\n\n\n"},{"id":"sKJ5","level":4,"heading":"Process Lock - Create","content":"
\n\n\nAllows a process to call acquire on a lock they have already acquired.\nWith Lock this would block and the process would be deadlocked.\n\n\n\n"},{"id":"9vCe","level":3,"heading":"Lock - Operations","content":"
\n\n\nAcquire decrements the counter.\nThe semaphore will never let the counter go below 0.\nAcquiring a counter at 0 blocks the thread until the counter increases.\n\n\n\n"},{"id":"XYTy","level":4,"heading":"Thread Semaphore - Basics Using With","content":"
Thread Semaphore - Basics Using With
\n\n
from threading import Semaphore
\n\nCreate:\n\n
semaphore_1 = Semaphore(lock_count)
\n\nUse:\n\n
with semarphore_1:\n\t...
\n\nAutomatically acquires and releases the semaphore.\n\n\n"},{"id":"12Vk","level":4,"heading":"Process Semaphore - Basics","content":"
\n\n\nAcquire decrements the counter.\nThe semaphore will nevere let the counter go below 0.\nAcquiring a counter at 0 blocks the process until the counter increases.\n\n\n\n"},{"id":"qLrW","level":4,"heading":"Process Semaphore - Basics Using With","content":"
Process Semaphore - Basics Using With
\n\n
from multiprocessing import Semaphore
\n\nCreate:\n\n
semaphore_1 = Semaphore(lock_count)
\n\nUse:\n\n
with semarphore_1:\n\t...
\n\nAutomatically acquires and releases the semaphore.\n\n\n\n"},{"id":"uCaT","level":3,"heading":"Semaphore - Create","content":"
\n\n\nOnly the acquiring thread or process can release a semaphore.\n\n\n\n"},{"id":"04gT","level":4,"heading":"Semaphore - With","content":"
Semaphore - With
\n\n
with Semaphore() as semaphore_1:\n\n\t...
\n\nAutomatically acquires and releases the semaphore.\n\n\n\n"},{"id":"5AT4","level":2,"heading":"Shared Memory - Value","content":"
Shared Memory - Value
\n\nCreates a synchronized value that can be shared between different processes.\n\n\n\n"},{"id":"z7be","level":3,"heading":"Shared Value - Basics","content":"
Shared Value - Basics
\n\n
from multiprocessing import Value
\n\nCreate:\n\n
shared_value_1 = Value(type, (arguments))
\n\nRetrieve:\n\n
current_value = shared_value_1.value
\n\nUpdate:\n\n
shared_value_1.value = new_value
\n\n\n\n"},{"id":"q3Hj","level":3,"heading":"Shared Value - Create","content":"
Shared Value - Create
\n\n\n\n"},{"id":"q3Jm","level":4,"heading":"Shared Value - Create","content":"
\n\n\n\n"},{"id":"bnGK","level":4,"heading":"Shared Value - Create Unsynchronized","content":"
Shared Value - Create Unsynchronized
\n\n
from multiprocessing import Value
\n\n
= Value(..., lock = False)
\n\n\nExample:\n\n
boolean_flag = Value(ctypes.c_bool, False)
\n\n\n\n"},{"id":"s5Df","level":4,"heading":"Shared Value - Types","content":"
Shared Value - Types
\n\nFor:\n\n
= Value(type, ...)
\n\ntypectypes.c_bool\n\t\tctypes.c_char\n\t\tctypes.c_wthar\n\t\tctypes.c_int\n\t\tctypes.c_long\n\t\tctypes.c_float\n\t\tctypes.c_char_p\n\t\tctypes.c_wchar_p\n\t\tctypes.c_void_p\n\n\t\t'c' Same as ctype.c_char, 1-character bytes object\n\t\t'u' Same as ctype.c_wchar, 1-character string\n\t\t'i' Same as ctypes.c_int, int\n\t\t'l' Same as ctypes.c_long, int\n\t\t'f' Same as ctypes.c_float, float\n\n\ntype is a C-Type value.\n\n\nExample:\n\n
integer_1 = Value(ctypes.c_int)
\n\n
integer_2 = Value('i')
\n\n\n\n"},{"id":"Yhza","level":3,"heading":"Shared Value - Operations","content":"
Shared Value - Operations
\n\n\n\n"},{"id":"NS1L","level":4,"heading":"Shared Value - Get Value","content":"
Shared Value - Get Value
\n\n
= value_1.value
\n\n\n\n"},{"id":"rsKg","level":4,"heading":"Shared Value - Update Value","content":"
Shared Value - Update Value
\n\n
value_1.value = new_value
\n\n\n\n"},{"id":"rVhk","level":4,"heading":"Shared Value - Get Lock","content":"
\n\nDefines a coroutine that can be scheduled to run on an event loop.\n\n\n\n"},{"id":"vRTA","level":2,"heading":"Async For","content":"
Async For
\n\n
async for item in async_iterable:\n\t...
\n\n\nUse with asyncronous iterables.\n\n\nExample:\n\n
class AsyncIterable1:\n\tdef __aiter__(self):\n\t\treturn self\n\n\tasync def __anext__(self):\n\t\tnext = await get_next()\n\t\treturn next\n\n\nasync for item in AsyncIterable1:\n\t...
async with AsyncClass1() as async_1:\n\t...\n\tawait async_1.action()
\n\n\nUse with classes that use the asynchronous context manager.\n\n\nExample:\n\n
class AsyncClass1:\n\n\tasync def __aenter__(self):\n\t\t...\n\n\tasync def __aexit__(self, exc_type, exc, tb):\n\t\t...\n\n\nasync with AsyncClass1() as async_1:\n\t...
\n\n\nSuspends operations and returns control from a coroutine function while it waits for the future or function to complete.\n\n\n\n"},{"id":"uXHP","level":2,"heading":"Asyncio Sleep","content":"
\n\nSuspends the current coroutine immediately.\nReleases control back to the event loop so it can process other coroutines.\nExecution returns to this immediately after the other tasks in the event loop have run.\n\n\n\n"},{"id":"mN6E","level":2,"heading":"Asyncio Sleep - Until Given Time","content":"
\n\n\n\n"},{"id":"2fZ1","level":4,"heading":"Coroutine - Start Main Coroutine","content":"
Coroutine - Start Main Coroutine
\n\n
run(main())
\n\nUsage:\n\n
from asyncio import run\n\nasync def main():\n\t...\n\nrun(main())
\n\n\nThis is a typical way to start your threads running.\nIt runs main() on the main event loop.\n\n\n\n"},{"id":"X2SV","level":4,"heading":"Coroutine - Run with await","content":"
Coroutine - Run with await
\n\nDefine Coroutine Function:\n\n
async def coroutine_function_1():\n\t...
\n\nCall:\n\n
await coroutine_function_1()
\n\n
result = await coroutine_function_2()
\n\n\nDefine the coroutine with async def.\nawait calls and then blocks until the coroutine completes.\n\n\n\n"},{"id":"NcsT","level":4,"heading":"Coroutine - Run as Task","content":"
Coroutine - Run as Task
\n\n
from asyncio import create_task
\n\nDefine:\n\n
async def coroutine_function():\n\t...
\n\nSchedule Execution:\n\n
task_1 = create_task(coroutine_function())
\n\nComplete?:\n\n
= task_1.done()
\n\nGet Result:\n\n
= task_1.result()
\n\n\n\nDefine the coroutine with async def.\nSchedule the coroutine to run with create_task().\nCheck it is complete with .done().\nGet the final result with .result().\n\n\n\n"},{"id":"bkuH","level":3,"heading":"Coroutine - Life Cycle","content":"
\n\n\nCoroutines start out as coroutine functions defined with async def.\n\nThey become coroutines (sometimes called coroutine object) when the function is called. The coroutine is not running yet.\n\nThere are at least 2 options to run it:\n\n\tCall with await\n\tCreate a Task\n\nCall with await will run the coroutine immediately and wait for a result. await must be called inside another coroutine.\n\nCreate a Task with create_task(). This will schedule the coroutine on the current event loop and will execute it once the event loop completes it's other tasks.\n\n\n\n"},{"id":"8P3p","level":3,"heading":"Coroutine - Create","content":"
\n\n\nDefines a coroutine function that can be scheduled on the event loop.\n\n\n\n"},{"id":"0bQ3","level":4,"heading":"Coroutine - Create Coroutine","content":"
Coroutine - Create Coroutine
\n\nTo Coroutine:\n\n
coroutine_1 = coroutine_function_1()
\n\n\nThis is an intermediate step that is usually done directly within await or create_task().\n\n\n\n"},{"id":"Mupd","level":3,"heading":"Coroutine - Operations","content":"
\n\n\nawait blocks until the coroutine completes.\nCan only be called from within another coroutine.\n\n\n\n"},{"id":"JnPF","level":4,"heading":"Coroutine - Call, Wait For Result / await","content":"
Coroutine - Call, Wait For Result / await
\n\n
result = await coroutine_function_1()
\n\nor\n\n
result = await coroutine_1
\n\n\nawait blocks until the coroutine completes.\nCan only be called from within another coroutine.\n\n\n\n"},{"id":"6Mnp","level":4,"heading":"Coroutine - Schedule Execution","content":"
Coroutine - Schedule Execution
\n\n
from asyncio import create_task
\n\n
task_1 = create_task(coroutine_function_1())
\n\nor\n\n
task_1 = create_task(coroutine_1)
\n\n\nOnce converted to a task, the coroutine is scheduled to run on the current event loop.\n\n\n\n"},{"id":"FJS8","level":4,"heading":"Coroutines - Chain Sequentially","content":"
Coroutines - Chain Sequentially
\n\n
await subfunction_1()\nawait subfunction_2()\n...
\n\n\nUse await to run coroutines sequentially.\n\n\n\n"},{"id":"DR6P","level":4,"heading":"Coroutines - Chain Sequentially With Chaining Function","content":"
Coroutines - Chain Sequentially With Chaining Function
\n\n\nchaining_function chains subroutines together and runs them sequentially.\nGet the final result by calling chaining_function() with await.\n\n\n\n"},{"id":"NeXD","level":4,"heading":"Coroutines - Run 'In Parallel'","content":"
\n\nResponsible for getting items from an event queue and processing them.\n\n\n\n"},{"id":"adj8","level":3,"heading":"Event Loop - Life Cycle","content":"
Event Loop - Life Cycle
\n\nThe event loop stores tasks in a queue.\nThe event loop calls the first/next task in that queue.\n\nThe task runs until it suspends itself, releasing control back to the event loop.\n\nThe event loop resumes the task\n\tonce the io/external operation completes.\n\n\n\n"},{"id":"fwWn","level":3,"heading":"Event Loop - Create / Get","content":"
from asyncio import new_event_loop()\n\nevent_loop = new_event_loop()
\n\n\nReturns: Subclass of AbstractEventLoop\n\n\nThis event loop runs in the current thread by default.\n\n\n\n"},{"id":"z10r","level":4,"heading":"Event Loop - Start on Main Loop","content":"
Event Loop - Start on Main Loop
\n\n
run(main())
\n\nUsage:\n\n
from asyncio import run\n\nasync def main():\n\t...\n\nrun(main())
\n\n\nThis is a typical way to start your threads running.\nIt runs main() on the main event loop.\n\n\n\n"},{"id":"FSCs","level":4,"heading":"Event Loop - Start on Main Loop (Verbose Version)","content":"
Event Loop - Start on Main Loop (Verbose Version)
\n\n
get_event_loop().run_until_complete(main())
\n\nUsage:\n\n
from asyncio import get_event_loop\n\nasync def main():\n\t...\n\nloop = get_event_loop()\nloop.run_until_complete(main())\nloop.close()
\n\n\nThis is a typical way to start your threads running.\nIt runs main() on the main event loop.\n\n\n\n"},{"id":"cU9j","level":4,"heading":"Event Loop - Get Main Loop","content":"
Event Loop - Get Main Loop
\n\n
from asyncio import get_event_loop()
\n\n
= get_even_loop()
\n\n\nReturns: Subclass of AbstractEventLoop\n\n\n\n"},{"id":"Zz1B","level":3,"heading":"Event Loop - Operations","content":"
\nAn object that is a proxy for a future result that has yet to be computed.\n\n\n\n"},{"id":"PnhF","level":3,"heading":"Future - Cancel","content":"
Future - Cancel
\n\n
= future_1.cancel()
\n\n\nReturns: bool\n\n\nAttempts to cancel a request.\nReturns True if successful.\n\n\n\n"},{"id":"SNv5","level":3,"heading":"Future - Is Complete?","content":"
Future - Is Complete?
\n\n
= future_1.done()
\n\n\n\n"},{"id":"pL8w","level":3,"heading":"Future - Get Value","content":"
Future - Get Value
\n\n
= future_1.result()
\n\n\n.result() never blocks even if the result is not available.\n\n\n\n"},{"id":"UqbD","level":3,"heading":"Future - Get With Exception Handling","content":"
Future - Get With Exception Handling
\n\n
try:\n\tresult = future_1.result()\nexcept Exception as exception:\n\t...
\n\n\nExceptions are returned through the future itself.\n\n\n\n"},{"id":"3pD2","level":3,"heading":"Future - Get Exception","content":"
Future - Get Exception
\n\n
= future_1.exception()
\n\n.exception() never blocks.\n\n\n\n"},{"id":"q5mw","level":3,"heading":"Future - Add Callback Function","content":"
Future - Add Callback Function
\n\n
= future_1.add_done_callback(callback_function)
\n\n\ncallback_fuction is called once the future completes.\nExceptions are not returned to the callback function.\n\n\n\n"},{"id":"HVy1","level":2,"heading":"Asyncio Task","content":"
Asyncio Task
\n\nSubclass of Future.\nWraps and manages the execution of a coroutien in an event loop.\n\n\n\n"},{"id":"pGAk","level":3,"heading":"Task - Operations","content":"
Task - Operations
\n\n\n\n"},{"id":"JeCV","level":4,"heading":"Create Task From Future / Coroutine Object","content":"
Create Task From Future / Coroutine Object
\n\n
from asyncio import create_task
\n\n
= create_task(coroutine_function_1())
\n\n\nThe task is placed on the event loop and scheduled to run.\nDefaults to the default event loop.\n\n\n\n"},{"id":"JeDX","level":4,"heading":"Create Task From Future / Coroutine Object","content":"
Create Task From Future / Coroutine Object
\n\n
from asyncio import ensure_future
\n\n
= ensure_future(coroutine_function_1())
\n\n
= ensure_future(coroutine_object_1)
\n\n
= ensure_future(future_)
\n\n
= ensure_future(..., loop = event_loop_1)
\n\n\nThe task is placed on the event loop and scheduled to run.\nDefaults to the default event loop.\n\n\n\n"},{"id":"hCwE","level":4,"heading":"Task - Cancel","content":"
Task - Cancel
\n\n
= task_1.cancel()
\n\n\nReturns: bool\n\n\nAttempts to cancel a request.\nReturns True if successful.\n\n\n\n"},{"id":"JqBh","level":4,"heading":"Task - Is Complete?","content":"
Task - Is Complete?
\n\n
= task_1.done()
\n\n\n\n"},{"id":"uJS4","level":4,"heading":"Task - Get Value","content":"
Task - Get Value
\n\n
= task_1.result()
\n\n\n.result() never blocks even if the result is not available.\n\n\n\n"},{"id":"GuKe","level":4,"heading":"Task - Get With Exception Handling","content":"
Task - Get With Exception Handling
\n\n
try:\n\tresult = task_1.result()\nexcept Exception as exception:\n\t...
\n\n\nExceptions are returned through the task itself.\n\n\n\n"},{"id":"3eYF","level":4,"heading":"Task - Get Exception","content":"
Task - Get Exception
\n\n
= task_1.exception()
\n\n.exception() never blocks.\n\n\n\n"},{"id":"MyJY","level":4,"heading":"Task - Add Callback Function","content":"
Task - Add Callback Function
\n\n
= task_1.add_done_callback(callback_function)
\n\n\nExceptions are not returned the the callback function.\n\n\n\n"},{"id":"aK8N","level":4,"heading":"Task - Get Name","content":"
Task - Get Name
\n\n
= task_1.get_name()
\n\n\n\n\n"},{"id":"kCFc","level":4,"heading":"Task - Set Name","content":"
\n\n\nSchedules futures for execution together.\nTimeout does not cancel futures.\n\n\n\n"},{"id":"A0Ta","level":3,"heading":"Futures / Tasks - Process As Completed","content":"
Futures / Tasks - Process As Completed
\n\n
from asyncio import as_completed
\n\n
for task in as_completed(futures):\n\tresult = await task
\n\n\nReturns tasks as they are completed.\nInternally it sets up a call back function that yields a task when it completes.\n\n\n\n"},{"id":"Qf9g","level":3,"heading":"Futures / Tasks - Wait, Gather Results","content":"
Futures / Tasks - Wait, Gather Results
\n\n
from asyncio import gather
\n\n
results = await gather(*futures)
\n\n\nReturns: List of results\n\n\nWaits for all futures to complete and then returns the results.\nThe order of the results is the same order as the tasks were submitted.\n\n\n\n"},{"id":"epjX","level":2,"heading":"Asyncio - Popular Asyncio Libraries","content":"
Asyncio - Popular Asyncio Libraries
\n\nI/O:\n\naiofiles\t\t\tAsynchronous File I/O\naiohttp\t\t\t\tAsynchronous Web Requests (SpeedSheet)\n\nDatabases:\n\naiomysql\t\t\tAsynchronous MySql Library\naiopg\t\t\t\tAsynchronous PostgreSql Library\naiocouchdb\t\t\tAsynchronous Couch DB Library\naiocassandra\t\tAsynchronous Cassandra Library\n\n\nOther Libraries:\nhttps://github.com/python/asyncio/wiki/ThirdParty\n\n\n\n"},{"id":"0LcE","level":1,"heading":"CSV","content":"
CSV
\n\n\n"},{"id":"LCJV","level":2,"heading":"CSV File - Read To Dict - With Header","content":"
CSV File - Read To Dict - With Header
\n\n
= DictReader(file)
\n\n
from csv import DictReader\n\nwith open(file_name) as file:\n\n\treader = DictReader(file)\n\n\tfor row in reader:\n\t\t...
\n\n\nEach row returns the row of values as a dict.\nThe keys are set by the header row (1st line in the CSV file).\nRequires a header row.\n\n\nExample:\n\n
file_name = 'path/data_file.csv'\nwith open(file_name) as file:\n\n\treader = DictReader(file)\n\tdata = [row for row in reader]
\n\n\n\n"},{"id":"5fCm","level":2,"heading":"CSV File - Read To Dict - Without Header","content":"
CSV File - Read To Dict - Without Header
\n\n
= DictReader(file, fieldnames = field_names)
\n\n
from csv import DictReader\n\nwith open(file_name) as file:\n\n\treader = DictReader(file, fieldnames = field_names)\n\n\tfor row in reader:\n\t\t...
\n\n\nSet the field names using the fieldnames option.\nPass the field names as a list of strings.\nEach row returns the row of values as a dict.\n\n\nExample:\n\n
file_name = 'path/data_file.csv'\nwith open(file_name) as file:\n\n\treader = DictReader(file, ["name", "date", "value"])\n\tdata = [row for row in reader]
\n\n\n\n"},{"id":"MZwj","level":2,"heading":"CSV File - Read To List - With Header","content":"
CSV File - Read To List - With Header
\n\n
= csv.reader(file)
\n\n
import csv\n\nwith open(file_name) as file:\n\n\treader = csv.reader(file)\n\n\theader = next(reader)\n\tfor row in reader:\n\t\t...
\n\n\nheader contains the fields returned from the first row as a list of strings.\nEach row returns the row of values as a list.\n\n\nExample:\n\n
file_name = 'path/data_file.csv'\nwith open(file_name) as file:\n\n\treader = csv.reader(file)\n\theader = next(reader)\n\tdata = [row for row in reader]
\n\n\n\n"},{"id":"GSq8","level":2,"heading":"CSV File - Read To List - Without Header","content":"
CSV File - Read To List - Without Header
\n\n
= csv.reader(file)
\n\n
import csv\n\nwith open(file_name) as file:\n\n\treader = csv.reader(file)\n\n\tfor row in reader:\n\t\t...
\n\n\nExample:\n\n
file_name = 'path/data_file.csv'\nwith open(file_name) as file:\n\n\treader = csv.reader(file)\n\tdata = [row for row in reader]
\n\n\n\n"},{"id":"Gp4H","level":2,"heading":"CSV File - When Reading Blank Lines","content":"
CSV File - When Reading Blank Lines
\n\nUsing csv.reader():\n\n
Returns a blank line as an empty list [].\nThe last line is ignored if blank.
\n\nUsing DictReader:\n\n
Ignores all blank lines.
\n\n\n\n"},{"id":"Vp7M","level":2,"heading":"CSV File - Write From Dict","content":"
\n\nAutomatically handled.\n\nThe csv library handles escaping quotes in values automatically.\nWhen reading values, string values are automatically unescaped with extra quotes removed.\nWhen writing, strings will be automatically escaped and then placed inside double quotes.\n\nEscaped Double Quotes: ""\n\n\n\n\n"},{"id":"uLDS","level":2,"heading":"CSV Option - Delimiter","content":"
\n\n\n\n"},{"id":"Dq3j","level":3,"heading":"Dataclass - Define With Comparison Functions","content":"
Dataclass - Define With Comparison Functions
\n\n
@dataclass(order=true)
\n\nUsage:\n\n
from dataclasses import dataclass\n\n@dataclass(order=true)\nclass Dataclass1:\n\t...
\n\n\nAdds comparison functions to the dataclass.\n\nComparisons are done in order by field.\n\n\nImplements:\n\n__lt__(), __le__(), __gt__(), and __ge__()\n\n\n\n"},{"id":"WfKY","level":3,"heading":"Dataclass - Define Immutable","content":"
\n\n\nThe class properties can not be changed.\n\nThis also implements __hash__().\n\n\n\n"},{"id":"r2UH","level":3,"heading":"Dataclass - Define Constructor - Override","content":"
\n\n\nYou can override the constructor if you need.\nConsider using __post_init__() instead.\n\n\n\n"},{"id":"Ku9y","level":3,"heading":"Dataclass - Define Constructor - Post Init","content":"
\n\n\n__post_init__ is called after the class is created.\nAdd any setup code you need in here including calling super().\n\n\n\n"},{"id":"HqzZ","level":3,"heading":"Dataclass - Define Constructor - Call Parent Constructor","content":"
\n\n\nUse __post_init__ to add a call to the parents constructor and addsuper().__init__().\n\n\n\n### Dataclass - Define Method\n\nWorks the same as a normal class.\n\nDefine:\n\n
\n\nA double ended queue that is implemented as a linked list under the hood.\n\nGuarantees O(1) performance for append, remove on either end of the queue.\n\n\n\n"},{"id":"RfJQ","level":3,"heading":"Deque - Basics","content":"
Deque - Basics
\n\n
from collections import deque\n\nqueue_1 = deque()\n\nqueue_1.append(value)\t\t\t# Append End / Right\nqueue_1.appendleft(value)\t\t# Append Start / Left\n\nlast = queue_1.pop()\t\t\t# Pop End / Right\nfirst = queue_1.popleft()\t\t# Pop Start / Left\n\nsize = len(queue_1)\nitem = queue_1[1]\n\ndel queue_1[1]\nqueue_1.clear()
\n\n\nCreates an empty queue.\n\n\n\n"},{"id":"273C","level":4,"heading":"Deque - Create From List","content":"
Deque - Create From List
\n\n
= deque(list_1)
\n\nUsage:\n\n
from collections import deque\n\n= deque(list_1)\n\n= deque([value_1, value_2, ...])
\n\n\n\n"},{"id":"JTuz","level":4,"heading":"Deque - Create With Maximum Size","content":"
Deque - Create With Maximum Size
\n\n
= deque(maxlen = size)
\n\nUsage:\n\n
from collections import deque\n\n= deque(maxlen = size)
\n\n\nSets the maximum size of deque().\n\nThe oldest item is removed when adding an item to a full deque.\n\n\n\n"},{"id":"R3mv","level":3,"heading":"Deque - Operations","content":"
\n\n\n\n"},{"id":"9CLJ","level":4,"heading":"Deque - Is Empty?","content":"
Deque - Is Empty?
\n\n
= not queue_1
\n\n
if not queue_1:\n\t...
\n\n\n\n"},{"id":"ednC","level":4,"heading":"Deque - Not Empty?","content":"
Deque - Not Empty?
\n\n
= bool(queue_1)
\n\n
if queue_1:\n\t...
\n\nUse bool() if you need to get a True/False value.\nThere is no need for bool() when using if....\n\n\n\n"},{"id":"WcPx","level":4,"heading":"Deque - Get","content":"
Deque - Get
\n\n
= queue_1[index]
\n\n\nReturns an item on the queue.\n\n\nExample:\n\n
\n\n\nRotates (shifts) the queue to the right count times by taking the last items and placing them at the start of the queue.\nRotates in place.\n\n\nExample:\n\n
from collections import deque\n\nqueue_1 = deque([1, 2, 3])\n\nqueue_1.rotate(2)\n\n# Sets queue_1 To: [2, 3, 1]
\n\nNamed tuples allow you to access tuple values by name.\n\nUse the namedtuple function to create a class for a given tuple type.\n\n\nPython Docs: Named Tuples\n\n\n\n"},{"id":"zhQE","level":3,"heading":"Named Tuple - Video Tutorial","content":"
Named Tuple - Video Tutorial
\n\nGet going faster with our Named Tuples in a Hurry Video:\n\n
from collections import OrderedDict\n\n= OrderedDict()
\n\n
= OrderedDict({key: value, key: value, ...})
\n\n\nReturns a dict where the keys are stored in insertion order.\nSubclasses the dict type.\n\nAll dict operations work on ordered dict.\n\n\nExample:\n\n
from collections import OrderedDict\n\ndict_1 = OrderedDict()\n\ndict_1['c'] = 'First'\ndict_1['b'] = 'Second'\ndict_1['a'] = 'Third'\n\nfor key in dict_1.keys():\n\tprint (key, dict_1[key])\n\n# Prints:\n#\n# c First\n# b Second\n# a Third
\n\n\n"},{"id":"XVry","level":4,"heading":"Ordered Dict - Get Keys","content":"
Ordered Dict - Get Keys
\n\n
= dict_1.keys()
\n\nReturns: odict_keys\n\n\nReturns the keys in insertion order.\n\n\n
from collections import OrderedDict\n\ndict_1 = OrderedDict()\n\ndict_1['c'] = 'First'\ndict_1['b'] = 'Second'\ndict_1['a'] = 'Third'\n\nfor key in dict_1.keys():\n\tprint (key, dict_1[key])\n\n# Prints:\n#\n# c First\n# b Second\n# a Third
\n\n\n\n"},{"id":"XkxL","level":4,"heading":"Ordered Dict - Get Item","content":"
Ordered Dict - Get Item
\n\n
= list(dict_1.items())[index]
\n\nReturns: value\n\n\nReturns an item.\n\nThe index references the item based on the insert order.\n\n\nExample:\n\n
\n\n\nAsserts an expression is true.\n\nIf false, rasises AssertionError.\nUse to debug code or alert of unexpected conditions.\n\n\n"},{"id":"KbV2","level":2,"heading":"Anything - Convert To String","content":"
Anything - Convert To String
\n\n
= repr(variable|expression)
\n\nConverts any value to a machine intrepretable string.\n\n\n\n"},{"id":"Wsaq","level":2,"heading":"Bash - Make Python File Executable","content":"
Bash - Make Python File Executable
\n\nPython File - 1st Line:\n\n
#!/usr/bin/env python3
\n\nMake Executable:\n\n
chmod +x file_name.py
\n\n\n1. Add the shebang to the file.\n2. Set the file as executable.\n\n\nAdding a shebang to the top of the script allows Bash to run it without explicitly having to tell it to use Python. \n\n\n\n"},{"id":"RWJd","level":3,"heading":"1 - Add Shebang","content":"
1 - Add Shebang
\n\n
#!/usr/bin/env python3
\n\nCalled the shebang.\nAdd to the first line in your file.\n\n\n\n"},{"id":"2b3V","level":3,"heading":"2 - Set File As Executable","content":"
2 - Set File As Executable
\n\n
chmod +x file_name.py
\n\nMakes the file executable.\n\n\n\n"},{"id":"RwcP","level":2,"heading":"Bitwise Not","content":"
\n\n\nPrints the byte code operations for the given function or class.\n\n\n\n"},{"id":"xWac","level":2,"heading":"Command-line Arguments - Get","content":"
Command-line Arguments - Get
\n\n
from sys import argv\n\narguments = argv[1:]
\n\nUse argv[1:] to return arguments.\n.argv[0] returns the module file name.\n\n\n\n"},{"id":"xWsH","level":2,"heading":"Command-line Arguments - Has","content":"
Command-line Arguments - Has
\n\n
from sys import argv\n\n= len(argv) > 1
\n\n\nReturns True when the program has command-line arguments.\n\n\n\n"},{"id":"HEGn","level":2,"heading":"Cached Compiled Files - Delete","content":"
Cached Compiled Files - Delete
\n\nBash:\n\n
find . -type f -name '*.py[co]' -delete -o -type d -name __pycache__ -delete
\n\n\nDeletes all __pycache__ directories in your project.\n\n\n\n"},{"id":"dtAz","level":2,"heading":"Console Screen - Clear","content":"
Console Screen - Clear
\n\nUse This Function:\n\n
from os import system, name\n\ndef clear_screen():\n if name == 'nt':\n system('cls')\t# Windows\n else:\n system('clear')\t# Mac, Linux
\n\nCall:\n\n
clear_screen()
\n\n\nClears the console screen.\n\n\n\n"},{"id":"XBng","level":2,"heading":"Current Working Directory - Get","content":"
Current Working Directory - Get
\n\n
from os import getcwd\n\ndirectory = getcwd()
\n\n\n\n"},{"id":"UsMJ","level":2,"heading":"Current Working Directory - Change","content":"
Current Working Directory - Change
\n\n
from os import chdir\n\nchdir(new_directory)
\n\n\n\n"},{"id":"7sp6","level":2,"heading":"Email - Send Basic Text Email","content":"
\n\n\nEvaluates the python expression and returns the value.\nThe expression can contain local and global variables.\n\nSyntax errors will raise SyntaxError.\nReferencing non-existent variables will raise NameError.\n\n\nExamples:\n\n
\n\n\nReturns: dict\n\n\nReturns all symbols currently in global scope from the symbol table.\n\n\n\n"},{"id":"H83c","level":2,"heading":"Input - Read","content":"
def is_palindrome(word):\n return word == word[::-1]
\n\n\nTests if a word is a palindrome.\n\n\nNot sure why everyone is searching for this but here you go - Tim O'.\n\n\nExample:\n\n
def is_palindrome(word):\n return word == word[::-1]\n\nprint(is_palindrome("racecar"))\nprint(is_palindrome("not a palindrome"))\n\n# Prints:\n#\n# True\n# False
\n\n\n\n"},{"id":"HWzt","level":2,"heading":"Item - Copy - Deep Copy","content":"
Item - Copy - Deep Copy
\n\n
from copy import copy
\n\n
= deepcopy(item_1)
\n\nMakes a copy of any variable, particularly objects or collections.\nAll child objects will also be replicated.\nThe new item will be completely independent of the original.\n\n\n\n"},{"id":"kBC4","level":2,"heading":"Item - Copy - Shallow Copy","content":"
Item - Copy - Shallow Copy
\n\n
from copy import copy
\n\n
= copy.copy(item_1)
\n\nMakes a shallow copy of any variable, particularly objects or collections.\nAll child objects will be referenced from the new item.\n\n\n\n"},{"id":"71pb","level":2,"heading":"Item - dir - Show Methods, Attributes","content":"
Item - dir - Show Methods, Attributes
\n\n
dir(Class1)
\n\n
dir(instance_1)
\n\nPrints all available methods and attributes on an item.\nWorks for classes, class instances, functions, just about everything.\n\n\n\n"},{"id":"m39H","level":2,"heading":"Line Separator","content":"
Line Separator
\n\n
from os import linesep\n\n= linesep
\n\nReturns the OS specific new line character.\n\n\n\n"},{"id":"16Qd","level":2,"heading":"Local Symbols - Get","content":"
Local Symbols - Get
\n\n
= locals()
\n\n\nReturns: dict\n\n\nLocals returns all symbols currently in local scope from the local symbol table.\n\n\n\n"},{"id":"J0wW","level":2,"heading":"Logical Operator - XOR","content":"
Logical Operator - XOR
\n\n
= bool(a) != bool(b)
\n\nIf a, b Are Booleans:\n\n
= a != b
\n\n\nThere is no explicit XOR operator but != works just fine.\n\n\n\n"},{"id":"knb2","level":3,"heading":"Match - Match If in List","content":"
Match - Match If in List
\n\n
match item_1:\n case item_1 if item_1 in list_2:\n ...
\n\n\nWill match the case only when condition is met.\n\n\n
item_1 = 1\n\neven = [2, 4, 6, 8, 10]\nodd = [1, 3, 5, 7, 9]\n\nmatch item_1:\n case item if item in even: print('Even')\n case item if item in odd: print('Odd')\n case _: print("Didn't match value.")\n\nPrints: 'Odd'
\n\n\n#1 - Puts a space between items.\n\n#2 - Use when print(item_1) wouldn't work.\n\n\nPrints to the standard out.\nAutomatically moves to the next line.\n\n\n\n"},{"id":"Kc3P","level":2,"heading":"Print - Newline Only","content":"
Print - Newline Only
\n\n
print()
\n\nPrints an empty line.\n\n\n\n"},{"id":"1Du8","level":2,"heading":"Print - No Newline","content":"
Print - No Newline
\n\n
print('text...', end='')
\n\n\n\n"},{"id":"JtVj","level":2,"heading":"Print - No Separator","content":"
from setuptools import find_packages, setup\n\nsetup(\n\tname='app_name',\n\tversion='1.0.0',\n\tdescription='App description.',\n\tpackages=find_packages('src'),\n\tpackage_dir={'': 'src'}\n)
\n\nNote:\n'src' is the standard directory for the project source code. On many projects the source folder has the same name as the root directory. In these cases, change src to the correct name.\n\n\n\n"},{"id":"00Gx","level":2,"heading":"Python Home Directory","content":"
Python Home Directory
\n\n
from sys import prefix\n\npython_home_directory = prefix
\n\nThis is where Python thinks it's home directory is.\n\n\n\n"},{"id":"yqs0","level":2,"heading":"Python Module - Search Path","content":"
Python Module - Search Path
\n\n
import path from sys\n\nmodule_search_path = path
\n\n\nReturns the python module search path.\n\n\n\n"},{"id":"UB4S","level":2,"heading":"Python Module - Add Path","content":"
Python Module - Add Path
\n\n
import path from sys\n\npath.append(new_module_root_directory
\n\n\nAdds a directory to the sources for python modules and scripts.\n\n\n\n"},{"id":"vd4q","level":2,"heading":"Python Version","content":"
Python Version
\n\n
import sys\n\nversion = sys.version\t\t\t\t\t# Text Form of Version Number
\n\n
= sys.version_info\t\t\t\t\t\t# Properties major, minor, And micro
\n\n\n\n"},{"id":"Vt6z","level":2,"heading":"Python Version - Descriptive","content":"
Python Version - Descriptive
\n\n
from sys import version\n\ndescriptive_version = version
\n\nIncludes version number, build date, clang version.\n\n\n\n"},{"id":"u9YV","level":2,"heading":"Show Help","content":"
Show Help
\n\n
help(item)
\n\nShows help documentation for item.\nWill display the docstring if available.\nWorks for keywords, functions, classes, methods, or modules.\n\n\n\n"},{"id":"Yph1","level":2,"heading":"Sleep","content":"
Sleep
\n\n
from time import sleep\n\nsleep(time_in_seconds)
\n\nSleep for the time in seconds.\n\nTakes floats (0.030 = 30 ms).\nWill pause current thread to allow other threads to run.\n\n\nExample:\n\n
from time import sleep\n\nsleep(1.5)\n# Sleep 1½ seconds.
\n\n\n\n"},{"id":"0Crn","level":2,"heading":"Sleep - Until Given Time","content":"
Sleep - Until Given Time
\n\nFunction:\n\n
from datetime import datetime\nfrom time import sleep\n\ndef slee_until(datetime_1):\n\tsleep((datetime_1 - datetime.now()).total_seconds())
\n\nCall:\n\n
sleep_until(datetime_1)
\n\nSleeps until the given time has passed.\nWorks fine for sub-second times.\n\n\n\n"},{"id":"dQM4","level":2,"heading":"System - Exit, Return Exit Code","content":"
System - Exit, Return Exit Code
\n\n
import sys\n\nsys.exit(exit_code)
\n\nReturns from execution with the given exit code.\n\nRecommended Exit Codes:\n\n\t0\tOK\n\t1\tGeneral Error\n\t2\tCommand-line Validation\n\n\n\n"},{"id":"Je4g","level":2,"heading":"System - Exit, Return Exit Messages","content":"
System - Exit, Return Exit Messages
\n\n
import sys\n\nsys.exit(exit_message)
\n\nReturns from execution with error code 1.\nPrints exit_message.\n\n\n\n"},{"id":"DWQg","level":2,"heading":"Timer - Measure Elapsed Time","content":"
Timer - Measure Elapsed Time
\n\n
from time import perf_counter\n\nstart = perf_counter()\n...\nend = perf_counter()\n\ndifference_in_seconds = end - start
\n\nReturns: float\n\n\nperf_counter() returns the elapsed time in seconds,\nPrefer over time.time() as perf_counter() is more accurate.\n\n\n\n"},{"id":"ZAZj","level":2,"heading":"Timer - Measure Execution Time (CPU Time)","content":"
Timer - Measure Execution Time (CPU Time)
\n\n
from time import process_time\n\nstart = process_time()\n...\nend = process_time()\n\ndifference_in_seconds = end - start
\n\nReturns: float\n\n\nprocess_time() returns the execution time (CPU time) in seconds as a float.\nDoes not measure time while a process is sleeping or suspended.\n\n\n\n"},{"id":"XKzM","level":2,"heading":"Timing - perf_counter() vs process_time() vs time()","content":"
Timing - perf_counter() vs process_time() vs time()
\n\nperf_counter():\n\n
Prefer over time() (more accurate).
\n
Measures elapsed time precisely.
\n
perf_counter -> Performance Counter
\n
import time.perf_counter
\n\nprocess_time():\n\n
Measures CPU time only.
\n
If the process sleeps, that time will not be tracked.
\n
import time.process_time
\n\ntime():\n\n
Measures absolute elapsed time.
\n
Not guaranteed to be accurate as it can be changed.
\n\n\n"},{"id":"LvNQ","level":3,"heading":"Format Integer - As Hex, Lower Case","content":"
Format Integer - As Hex, Lower Case
\n\n
= f'{value:x}'
\n\n
= '{:x}'.format(value)
\n\n\nFormat to lower case hex values using lower case 'x'.\n\n\nExamples:\n\n
value = 42\n\nprint(f'{value:x}')\n\n# Prints: 2a
\n\n
value = 42\n\nprint('{:x}'.format(value))\n\n# Prints: 2a
\n\n\n\n"},{"id":"p9qJ","level":3,"heading":"Format Integer - As Hex, Lower Case, Leading Zeros","content":"
Format Integer - As Hex, Lower Case, Leading Zeros
\n\n
= f'{int_1:0lengthx}'
\n\n
= '{:0lengthx}'.format(int_1)
\n\n\nFormat to lower case hex values using lower case 'x'.\nFormat with leading zeros by adding '0' and length after the ':'.\n\n\nExamples:\n\n
value = 42\n\nprint(f'{value:04x}')\n\n# Prints: 002a
\n\n
value = 42\n\nprint('{:04x}'.format(value))\n\n# Prints: 002a
\n\n\n\n"},{"id":"MrXC","level":3,"heading":"Format Integer - As Hex, Upper Case","content":"
Format Integer - As Hex, Upper Case
\n\n
= f'{value:X}'
\n\n
= '{:X}'.format(value)
\n\n\nFormat to upper case hex values using upper case 'X'.\n\n\nExamples:\n\n
value = 42\n\nprint(f'{value:X}')\n\n# Prints: 2A
\n\n
value = 42\n\nprint('{:X}'.format(value))\n\n# Prints: 2A
\n\n\n\n"},{"id":"M8bn","level":3,"heading":"Format Integer - As Hex, Upper Case, Leading Zeros","content":"
Format Integer - As Hex, Upper Case, Leading Zeros
\n\n
= f'{int_1:0lengthX}'
\n\n
= '{:0lengthX}'.format(int_1)
\n\n\nFormat to upper case hex values using upper case 'X'.\nFormat with leading zeros by adding '0' and length after the ':'.\n\n\nExamples:\n\n
value = 42\n\nprint(f'{value:04X}')\n\n# Prints: 002A
\n\n
value = 42\n\nprint('{:04X}'.format(value))\n\n# Prints: 002A
\n\n\n\n"},{"id":"2QJy","level":2,"heading":"Format - Date / Date Time","content":"
Format - Date / Date Time
\n\n
= f'{datetime_1:date_format}'
\n\n
= '{:date_format}'.format(datetime_1)
\n\n\n\n"},{"id":"wVNN","level":3,"heading":"Format Date - Date Format Codes","content":"
Format Date - Date Format Codes
\n\n
Item
Output
Symbol
\n
\n
Literal %\t\t
%\t\t
%%\t
\n
\t
\n
Day
1-31
%-d
\n
\t
01-31
%d
\n
\t
\n
Day of Week
0-6
%w
\n
\t
1-7
%u
(ISO 8601)
\n
\t
Mon
%a
\n
\t
Monday
%A
\n
\t
\n
Day of Year
1-365
%-j
\n
\t
001-365
%j
\n
\t
\n
Month
1-12
%-m
\n
\t
01-12
%m
\n
\t
Jan
%b
\n
\t
January
%B
\n
\t
\n
Week
0-53
%-U
(Starts Sunday)
\n
\t
00-53
%U
(Starts Sunday)
\n
\t
0-53
%-W
(Starts Monday)
\n
\t
00-53
%W
(Starts Monday)
\n
\t
0-53
%-V
(Starts Monday) (ISO 8601)
\n
\t
00-53
%V
(Starts Monday) (ISO 8601)
\n
\t
\n
Year
00-99
%y
\n
\t
2001
%Y
\n
\t
\n
Time Zone
%Z
\n
UTC Offset
%z
\n
\t
\n
Local Date
%x
\n
\t
\n
Local Date Time
%c
\n\n\n\n"},{"id":"AKvL","level":3,"heading":"Format Date - Time Format Codes","content":"
Format Date - Time Format Codes
\n\n
Item
Output
Symbol
\n
\t
\n
Literal %\t\t
%\t\t
%%\t
\n
\t
\n
Milliseconds
000000-999999
%f
\n
\t
\n
Second
00-59
%S
\n
\t
0-59
%-S
\n
Minute
00-59
%M
\n
\t
0-59
%-M
\n
\t
\n
Hour
00-12
%I
\n
\t
0-12
%-I
\n
\t
00-23
%H
\n
\t
0-23
%-H
\n
\t
\n
AM/PM
AM | PM
%p
\n
\t
\n
Time Zone
UTC
%Z
\n
\t
\n
UTC Offset
# -0500
%z
\n
\t
\n
Local Time
%X
\n\n\n\n"},{"id":"4DXk","level":3,"heading":"Format Date - HH:MM:SS","content":"
Format Date - HH:MM:SS
\n\nUsing F-String:\n\n
= f'{datetime_1:%H:%M:%S}'
\n\nUsing format():\n\n
= '{:%H:%M:%S}'.format(datetime_1)
\n\n\nReturns hour, minute, second.\n\n\n\n"},{"id":"NtPh","level":3,"heading":"Format Date - YYYY-MM-DD","content":"
Format Date - YYYY-MM-DD
\n\nUsing F-String:\n\n
= f'{datetime_1:%Y-%m-%d}'
\n\nUsing format():\n\n
= '{:%Y-%m-%d}'.format(datetime_1)
\n\nReturns year, month, day.\n\nWorks with dates and datetimes.\n\n\n\n"},{"id":"NYTQ","level":3,"heading":"Format Date - YYYY-MM-DD HH:MM:SS","content":"
Format Date - YYYY-MM-DD HH:MM:SS
\n\nUsing F-String:\n\n
= f'{datetime_1:%Y-%m-%d %H:%M:%S}'
\n\nUsing format():\n\n
= '{:%Y-%m-%d %H:%M:%S}'.format(date_1)
\n\n
= '{:%Y-%m-%d %H:%M:%S}'.format(datetime_1)
\n\nReturns year, month, day, hour, minute, second.\nFor dates will print time as '00:00:00'\n\n\n\n"},{"id":"gE4z","level":3,"heading":"Format Date - YYYY-MM-DD HH:MM:SS - Time Zone","content":"
Format Date - YYYY-MM-DD HH:MM:SS - Time Zone
\n\nUsing F-String:\n\n
= f'{datetime_1:%Y-%m-%d %H:%M:%S %Z}'
\n\nUsing format():\n\n
= '{:%Y-%m-%d %H:%M:%S %Z}'.format(date_1)
\n\n
= '{:%Y-%m-%d %H:%M:%S %Z}'.format(datetime_1)
\n\nReturns year, month, day, hour, minute, second and timezone.\nFor dates will print time as '00:00:00'\n\n\n\nash.#### Format Date - YYYY-MM-DD HH:MM:SS - UTC Offset\n\nUsing F-String:\n\n
= f'{datetime_1:%Y-%m-%d %H:%M:%S %z}'
\n\nUsing format():\n\n
= '{:%Y-%m-%d %H:%M:%S %z}'.format(date_1)
\n\n
= '{:%Y-%m-%d %H:%M:%S %z}'.format(datetime_1)
\n\nReturns year, month, day, hour, minute, second and utc offset.\nFor dates will print time as '00:00:00'\n\n\n\n"},{"id":"kADD","level":2,"heading":"Format Date - Standard Formats","content":"
Format Date - Standard Formats
\n\n\n"},{"id":"725q","level":3,"heading":"Format Date - Ireland / UK","content":"
Format Date - Ireland / UK
\n\nUsing F-String:\n\n
= f'{datetime_1:%d/%m/%Y}'
\n\nUsing format():\n\n
= '{:%d/%m/%Y}'.format(datetime_1)
\n\nFormat:\n\n
dd/mm/yyyy
\n\n\n\n"},{"id":"Js9w","level":3,"heading":"Format Date - Europe","content":"
Format Date - Europe
\n\nUsing F-String:\n\n
= f'{datetime_1:%d.%m.%Y}'
\n\nUsing format():\n\n
= '{:%d.%m.%Y}'.format(datetime_1)
\n\nFormat:\n\n
dd.mm.yyyy
\n\n\n\n"},{"id":"fdj6","level":3,"heading":"Format Date - USA","content":"
Format Date - USA
\n\nUsing F-String:\n\n
= f'{datetime_1:%m/%d/%Y}'
\n\nUsing format():\n\n
= '{:%m/%d/%Y}'.format(datetime_1)
\n\nFormat:\n\n
mm/dd/yyyy
\n\n\n\n"},{"id":"TkTa","level":3,"heading":"Format Date - ISO 8601 / International","content":"
Format Date - ISO 8601 / International
\n\nYYYY-MM-DD:\n\n
= f'{datetime_1:%Y-%m-%d}'
\n\n
= '{:%Y-%m-%d}'.format(datetime_1)
\n\nYYYYMMDD:\n\n
= f'{datetime_1:%Y%m%d}'
\n\n
= '{:%Y%m%d}'.format(datetime_1)
\n\n\n\n"},{"id":"FQkZ","level":3,"heading":"Format Date Time - ISO 8601 / International","content":"
\n\n\n%%\t\t\tEscaped %\n{{\t\t\tEscaped {\n}}\t\t\tEscaped }\n\n,\t\t\tComma Separated Numbers\n.2\t\t\tDecimal Places\n\n<10\t\t\tAlign Left / Pad Right\n>10\t\t\tAlign Right / Pad Left\n^10\t\t\tAlign Center\n\n010\t\t\tLeading Zeroes\n\nchar<10\t\tAlight Left, Fill Character char\nchar>10\t\tAlight Right, Fill Character char\nchar^10\t\tAlight Center, Fill Character char\n\n%%\t\t\tLiteral %\t\t\t%\n%-d\t\t\tDay \t\t\t1-31\n%-H\t\t\tHour\t\t\t0-23\n%-I\t\t\tHour\t\t\t0-12\n%-j\t\t\tDay of Year\t\t1-365\n%-M\t\t\tMinute\t\t\t0-59\n%-m\t\t\tMonth\t\t\t1-12\n%-S\t\t\tSecond\t\t\t0-59\n%-U\t\t\tWeek\t\t\t0-53 (Starts Sunday)\n%-V\t\t\tWeek\t\t\t0-53 (Starts Monday) (ISO 8601)\n%-W\t\t\tWeek\t\t\t0-53 (Starts Monday)\n%a\t\t\tDay of Week\t\tMon\n%A\t\t\tDay of Week\t\tMonday\n%b\t\t\tMonth\t\t\tJan\n%B\t\t\tMonth\t\t\tJanuary\n%c\t\t\tLocal Date Time\n%d\t\t\tDay\t\t\t\t01-31\n%f\t\t\tMilliseconds\t\t000000-999999\n%H\t\t\tHour\t\t\t00-23\n%I\t\t\tHour\t\t\t00-12\n%j\t\t\tDay of Year\t\t001-365\n%m\t\t\tMonth\t\t\t01-12\n%M\t\t\tMinute\t\t\t00-59\n%p\t\t\tAM/PM\t\t\tAM | PM\n%S\t\t\tSecond\t\t\t00-59\n%u\t\t\tDay of Week\t\t1-7\t (ISO 8601)\n%U\t\t\tWeek\t\t\t00-53 (Starts Sunday)\n%V\t\t\tWeek\t\t\t01-53 (Starts Monday) (ISO 8601)\n%w\t\t\tDay of Week\t\t0-6\n%W\t\t\tWeek\t\t\t00-53 (Starts Monday)\n%x\t\t\tLocal Date\n%y\t\t\tYear\t\t\t00-99\n%Y\t\t\tYear\t\t\t2001\n%z\t\t\tUTC Offset\t\t(e.g. -0500)\n%Z\t\t\tTime Zone\t\tUTC\n%X\t\t\tLocal Time\n\n\n\n"},{"id":"G5zB","level":1,"heading":"Reference - Magic Methods","content":"
\n\nReturns the true or false value of an object.\nReturn True for non zero, non empty values.\nUse with if statements or bool() function.\n\n\nExample:\n\n
class GetBoolean:\n\n\tdef __init__(self, bool_value):\n\t\tself.bool_value = bool_value\n\n\tdef __bool__(self):\n\t\treturn self.bool_value
\n\n
is_true = GetBoolean(True)\t\t\t\t# Set To True\n\nactual_value = bool(is_true)\t\t\t# Returns True
\n\n
is_true = GetBoolean(True)\t\t\t\t# Set To True\n\nif is_true:\n\t...
\n\n\nHashes the identity of an object.\n\nUse an object's keys to create hash.\nThe key should never change for the lifetime of the object.\nPrefer immutable objects over mutable ones.\n\n\nObject Identity vs Object Hash:\n\n
if a == b then\n hash(a) == hash(b)\n\nif hash(a) == hash(b) then\n a maybe == b\n\nif hash(a) != hash(b) then\n a != b
\n\nReturns an iterator usable with for and in statements.\nImplement this method if you want to return an iterator for your object.\n\nSee: __next__\nSee: Class - Iterator - Define\n\n\n\n"},{"id":"fzyZ","level":2,"heading":"__len___","content":"
__len___
\n\nReturns the length or count of an object.\nUse with len function.\n\n\nExample:\n\n
\n\n\nThe main/root module reference.\n\n\nWhy use __name__ == '__main__':\n\nUse this when you want to run a file as the main program and also as a module.\n__name__ will only be '__main__' when the file is the starting file / entry point into the program.\n\nAdd module classes and functions as normal.\nBut to run as a the main application, add code after the if statement.\n\nForm:\n\n
if __name__ == '__main__':\n\n\t# Code for main program here...
\n\nThe name of the object.\n\nFor modules, it is the file name (no extension).\n\ne.g. module, class or function name.\n\n\n\n"},{"id":"E5gQ","level":2,"heading":"__next__","content":"
__next__
\n\nIterator: Returns the next item in the collection.\nIterator: Raises an exception beyond the last point.\n\n\n\n"},{"id":"Q1w6","level":2,"heading":"__repr__","content":"
__repr__
\n\nReturns unambiguous string representation of the class.\nAlways implement this.\n\n\n\n"},{"id":"k9WJ","level":2,"heading":"__str__","content":"
__str__
\n\nReturns a readable string representation of the class.\nWill call __repr__ if no __str__() method found.\n\n\n\n"},{"id":"FgBf","level":2,"heading":"__repr__ vs __str__","content":"
__repr__ vs __str__
\n\n__repr__\n\n\tUse to show an unambiguous version of the class.\n\tYou should always implement this.\n\n__str__\n\n\tUse to show a human readable version of the class.\n\tIf not present, Python will call __repr__.\n\n\n\n"},{"id":"KxKn","level":1,"heading":"Reference - Standard Packages","content":"
\n\nUse list.\n\nPython does not have built in arrays.\nUse lists instead.\nYou can also use the Array library.\n\n\n\n"},{"id":"0bhw","level":2,"heading":"Arrow Functions, ->, =>","content":"
\n\nA function name leading with an at sign is a decorator\n\n\n\n"},{"id":"UkTt","level":3,"heading":"Symbol #","content":"
Symbol #
\nComment\n\n
# This is a comment
\n\nThe hash denotes a comment section at the end of a line.\n\n\n\n"},{"id":"UkUH","level":3,"heading":"Symbol ;","content":"
Symbol ;
\nStatement Separator\n\n
statement_1;
\n\nThe semicolon identifies the division between one statement and another.\nIt is not required in Python but is accepted.\n2 semicolon, statement separator\n\n\n\n"},{"id":"bYJ8","level":3,"heading":"Symbol *args","content":"
Symbol *args
\n\nArguments received as a tuple.\n\n
def function_1(*args):\n\t...
\n\nWhen calling the function, the sequence or list is converted to the function arguments in order.\nWhen the arguments as defined as *args in the function, arguments are converted to a tuple and then passed in.\n\n\n\n"},{"id":"mfSc","level":3,"heading":"Symbol **kwargs","content":"
Symbol **kwargs
\nKey Word Arguments\n\nDenotes arguments received by a function as a key value dict.\n\n
def function_1(**kwargs):\n\t...
\n\nWhen calling the function, the keys are mapped to the function's internal arguments by name.\nWhen the arguments are defined as **kwargs in the function, named arguments are converted to a dict and then passed in.\n\n\n\n"},{"id":"dGc5","level":3,"heading":"Symbol *list","content":"
Symbol *list
\nA sequence or list to be unpacked when calling a function.\n\nWhen calling a function, the sequence or list will be unpacked into parameter order before passing to the function.\n\n
\n\nEvaluates an expression, assigns it to the variable, and returns the result same expression..\n\n\n"},{"id":"UkVT","level":3,"heading":"Symbol ~","content":"
\n\nA reserved word is a keyword that has special meaning or purpose to Python.\nIt can not be used as the name of an object, variable or function.\n\n
\nAn argument passed into a function.\n\n\n\n"},{"id":"0L4d","level":2,"heading":"AWS","content":"
AWS
\nThis is used in coroutines and event loops.\n\nBest guess:\nAwaitable subroutine.\n\nSomeone who knows, can you please help us out and tell us what this stands for?\n\n\n\n"},{"id":"00fT","level":2,"heading":"FP","content":"
\nPython compiled module.\nCreated by interpreter when a module is imported.\n\n\n\n"},{"id":"PWJN","level":3,"heading":"Python File Extension .pyd","content":"
Python File Extension .pyd
\nWindows dynamic link library that contains a python module.\nCalled from other python applications.\n\n\n\n"},{"id":"DY4N","level":2,"heading":"REPL","content":"
\nBreaks a task into internal and external steps.\n\nThe external steps are submitted.\nThen the internal steps are performed.\nFinally the responses from the external steps are collected.\n\nThe external task is often represented by an object\ncalled future, promise or task.\n\nBest for I/O bound processes and Python threads.\n\n\n\n"},{"id":"4bp8","level":2,"heading":"Attribute","content":"
Attribute
\nA class variable or function. Anything you reference with '.' . \n\n\n\n"},{"id":"k60q","level":2,"heading":"Awaitable","content":"
Awaitable
\n\nAnything that can be used with await.\n\nMain types: coroutines, Tasks, and Futures\n\n\n\n"},{"id":"A0gG","level":2,"heading":"Class","content":"
Class
\nA class object defined in a module file. Classes should use Pascal case.\n\n\n\n"},{"id":"SVtP","level":2,"heading":"Class Member","content":"
Class Member
\nAny variable or function defined in the class.\n\nAll members are public.\n\n\n\n"},{"id":"RLqV","level":2,"heading":"Class Method","content":"
Class Method
\nStored as an attribute on a class.\n\n\n\n"},{"id":"4uvb","level":2,"heading":"Closure","content":"
Closure
\nIs a function that "closes over" the environment it was defined in. It has access to all the variables in that are in scope in that environment without having to explicitly have them passed in.\n\nThis applies to lambdas and nested functions.\n\n\n\n"},{"id":"qm07","level":2,"heading":"Constants","content":"
Constants
\nThere is no mechanism to enforce constants in Python.\n\nUse a regular variable, style it as a constant and trust your fellow developers to play by the rules!\n\n\n\n"},{"id":"XrTA","level":2,"heading":"Coroutine","content":"
Coroutine
\nA suspendable function for use in concurrent thread processes.\n\nIt can be stopped and restarted and will voluntarily yield control to other functions on the current thread instead of blocking.\nUse this to work on single threaded event loops.\n\n\n\n"},{"id":"LmhX","level":2,"heading":"Daemon Process","content":"
Daemon Process
\nA process that runs independently of its parent process.\n\nIt will continue to run when the parent terminates.\n\n\n\n"},{"id":"0Zb2","level":2,"heading":"Decorator","content":"
Decorator
\nA method or class that runs before a method is called.\n\nThe decorator method is applied with @decorator ('@' + decorator function name).\nNot related to the decorator pattern.\n\n\n\n"},{"id":"9UHw","level":2,"heading":"Deep vs Shallow Copying","content":"
Deep vs Shallow Copying
\n\nShallow Copy:\nCreates a copy of the parent object but reuses the original child objects.\n\nDeep Copy:\nCreates duplicates of the parent object and all related child objects.\nCan break if there are circular references.\n\n\n\n"},{"id":"ebPK","level":2,"heading":"Dictionary","content":"
Dictionary
\nA dict. A collection of key value pairs.\n\n\n\n"},{"id":"n8Vq","level":2,"heading":"Duck Typing","content":"
Duck Typing
\nIf it walks like a duck and quacks like a duck, it is a duck.\n\nDuck typing states that if the method exists, the object supports that action and you can invoke it.\nThere is no type checking to see if the object type or superclass explicitly supports that method.\n\n\n\n"},{"id":"mzHR","level":2,"heading":"Dunder Method","content":"
Dunder Method
\nAny method that stars and ends with a double underscore.\n\nExample: __name__\n\nDunder = Double Underscore\nSee: Magic Method\n\n\n\n"},{"id":"YVyv","level":2,"heading":"Egg File","content":"
Egg File
\nA zip file containing Python files. It is runnable if it contains __main__.py in the root directory.\n\n\n\n"},{"id":"LfsF","level":2,"heading":"Epoch","content":"
Epoch
\nThe time at Unix Time 0.\n\nJanuary 1st, 1970 at 00:00:00 UTC.\n\n\n\n"},{"id":"gBrV","level":2,"heading":"Epoch Time / Unix Time","content":"
Epoch Time / Unix Time
\nThe time that has passed in seconds since the Unix epoch (January 1st, 1970).\n\n\n\n"},{"id":"NqVS","level":2,"heading":"Event Loop","content":"
Event Loop
\nA single threaded process that places coroutines and tasks on a queue and executes them one at a time.\nThe task or coroutine will voluntarily give up control back to the event loop when blocked, allowing other tasks to continue.\n\nGreat for handling IO bound operations where you don't want to block execution when waiting for external operations to complete.\n\n\n\n"},{"id":"m1Tc","level":2,"heading":"Executable Directory","content":"
Executable Directory
\nAn executable directory is any directory containing __main__.py.\n\nWhen called from python, it will execute the code in __main__.py to start the application.\n\n\n\n"},{"id":"kCgF","level":2,"heading":"Expression","content":"
Expression
\nSome code that evaluates to a value.\n\nExamples:\n\n
\nAn f-string or string in the form f"text".\n\nUsed to create a formatted string.\n\n\n\n"},{"id":"wpbS","level":2,"heading":"Function","content":"
Function
\nA callable section of code that has a name, takes arguments and performs an action or calculation.\nPython functions can be stand alone or in a class.\n\n\n\n"},{"id":"eJxZ","level":2,"heading":"Function - Function Overloading","content":"
Function - Function Overloading
\nNot supported by Python.\n\nUse named argument passing or optional function arguments.\n\nFunction overloading is where multiple functions are defined with the same name but have different arguments. For Python, use named arguments with default values inside a single function instead.\n\n\n\n"},{"id":"dv58","level":2,"heading":"Function - Inner Function","content":"
Function - Inner Function
\nA function defined inside another function.\n\n\n\n"},{"id":"bfnv","level":2,"heading":"Generics","content":"
Generics
\nStrictly speaking not supported in Python.\n\nPython is a dynamic language and uses duck typing. No need for Generics.\n\nPython's typing library allows you to declare generic types but they are ignored by the compiler.\n\n\n\n"},{"id":"eW9y","level":2,"heading":"Global Interpreter Lock (GIL)","content":"
Global Interpreter Lock (GIL)
\nUsed by python to protect the interpreter's state during multitasking operations.\n\nPrevents multiple native threads from executing python code at the same time.\n\nIt is needed to prevent race conditions and dead locks with Python's memory management unit.\nIt is implemented as a mutex (lock) that allows only one thread to hold control of Python's interpreter.\nA thread must obtain the lock before it can execute.\nIO bound operations automatically release control to the GIL so other threads can run.\n\nSee: Multitasking, Thread\n\n\n\n"},{"id":"ZQsf","level":2,"heading":"Gorilla","content":"
Gorilla
\nHere is a gorilla \uD83E\uDD8D\n\n\n\n"},{"id":"C0zX","level":2,"heading":"Goto","content":"
Goto
\nNot supported in Python\n\n\n\n"},{"id":"BswV","level":2,"heading":"Green Threads","content":"
Green Threads
\nPython's mechanism for emulating multi-threading.\n\nThey are managed in user space instead of kernel space, enabling them to work in environments that do not have native thread support. They work like cooperative multi-threading. Each thread voluntarily/explicitly give up control to one another at specified points in your code.\n\nAlso called: Greenlets\n\n\n\n"},{"id":"EkAT","level":2,"heading":"Guido van Rossum","content":"
Guido van Rossum
\nThe creator of Python.\n\nGuido created Python in 1991.\n\n\n\n"},{"id":"3f5K","level":2,"heading":"Inter-Process Communication","content":"
Inter-Process Communication
\n\nUse any of these:\n\n\tPipe\n\tQueue\n\tShared Memory\n\tShared Manager\n\n\n\n"},{"id":"TAvT","level":3,"heading":"Inter-Process Communication - Shared Memory","content":"
Inter-Process Communication - Shared Memory
\n\n
multiprocessing.Value
\n\n
multiprocessing.Array
\n\n\nThese are faster than a shared manager but have restrictions.\n\n\n\n"},{"id":"LxdK","level":3,"heading":"Inter-Process Communication - Shared Manager","content":"
Inter-Process Communication - Shared Manager
\n\nSlower, uses proxy to write to shared memory.\nSupports a wider range of types (dicts, lists, semaphores, etc.)\n\nCan share memory over the network.\n\n\n\n"},{"id":"8MpC","level":2,"heading":"Iterable","content":"
Iterable
\nAny object that returns an iterator.\n\nUsed by any class that has data that can be iterated over.\n\n\n\n"},{"id":"8T9X","level":2,"heading":"Iterator","content":"
Iterator
\nAn object that iterates over a set of data.\n\nIt returns the data one element at a time.\n\n\n\n"},{"id":"ZGrb","level":2,"heading":"Kitchen Sink","content":"
Kitchen Sink
\nSo we might have lied about the kitchen sink. But we are doing our best to make this as complete as possible.\n\nLet us know what we should have in here but don't.\n\nAnd one day, we may also add the kitchen sink!\n\n\n\n"},{"id":"0Dwm","level":2,"heading":"Lazy Iterators","content":"
Lazy Iterators
\nThese iterators evaluate each value one at a time and only when required.\n\nExamples: Generator Expression, Yield\n\n\n\n"},{"id":"Xgz0","level":2,"heading":"Magic Method","content":"
Magic Method
\nA python language method that adds "magic" functionality to a class.\n\nReserved for system methods. These methods are always in the form __methodname__. The double underscores is a way of ensuring system method names don't collide with user names.\n\nAlso called: A Dunder method (double-underscore).\n\n\n\n"},{"id":"FXVt","level":2,"heading":"Map Data Structure","content":"
Map Data Structure
\nUse Python's dict for other languages' map() or dictionary() data structures.\n\n\n\n"},{"id":"13X9","level":2,"heading":"Memory Management","content":"
Memory Management
\nPython uses reference counting to track when objects become unused. When the count is 0, the object memory gets freed.\n\n\n\n"},{"id":"5jDa","level":2,"heading":"Method or Function Overloading","content":"
Method or Function Overloading
\nNot supported in Python.\n\nUse named argument passing or optional method arguments.\n\nUse default values in the method signatures and pass arguments by name.\n\n\n\n"},{"id":"2VMp","level":2,"heading":"Mixin","content":"
Mixin
\nA special kind of multiple inheritance.\n\nUsed to either: \n- provide a lot of optional features for a class.\n- use a particular feature in a lot of classes.\n\nFor the optional feature classes, these classes are not designed to stand alone but add some functionality to another class type.\n\n\n\n"},{"id":"25be","level":2,"heading":"Module","content":"
Module
\nA file that contains related Python definitions and statements. Should be short and lower case. Module names map to file names.\n\n\n\n"},{"id":"4hYJ","level":2,"heading":"Monkey Patch","content":"
Monkey Patch
\nPython's mechanism for changing the behaviour of a piece of code at runtime.\n\nFunctions or class methods can be changed dynamically while the application is running.\nUsually done for testing purposes (unit tests).\n\n\n\n"},{"id":"J6Nu","level":2,"heading":"Multitasking","content":"
Multitasking
\nPython implements multitasking through non-blocking event loops, multithreading or multiprocessing.\nEach has their benefits and costs.\n\n\n\n"},{"id":"vdhR","level":3,"heading":"Multitasking - Event Loops","content":"
Multitasking - Event Loops
\nRuns non blocking functions on a single threaded event loop.\nFunctions identify themselves as non-blocking and voluntarily give up control to the interpreter.\n\nThis has very little overhead and improves performance for IO bound operations.\nIt is slower than Multithreading but easier to code and is faster than sequential processing.\nAll core Python IO operations are non-blocking and work well.\n\n\n\n"},{"id":"hLMq","level":3,"heading":"Multitasking - Multithreading","content":"
Multitasking - Multithreading
\nPythons multitasking implementation using threads.\n\nIt allows cooperative multitasking and uses shared memory.\nIt is light weight and starts up fast but will not do true multitasking.\nThreads must voluntarily give up control to the interpreter.\nHowever, it is ideal for processing IO bound operations.\n\nSee: Threads\n\n\n\n"},{"id":"YD4M","level":2,"heading":"Multiprocessing","content":"
Multiprocessing
\nPythons multitasking implementation using processes.\n\nIt allows multitasking in separate memory spaces.\nIt is costly to start and does not share memory (by default) with other processes but it preforms true multitasking.\n\nSee: Process\n\n\n\n"},{"id":"af5J","level":2,"heading":"Namespace Package","content":"
Namespace Package
\nA package that is split across multiple root directories (those listed in sys.path) but with the same package name.\n\nPython scans all directories in sys.path for namespace packages.\nIf it finds package directories of the same name but no __init__.py file, it will treat them as one single package.\n\nCan not have __init__.py files.\nThis is to avoid the complexity and issues of deciding the order of running __init__ files.\n\n\n\n"},{"id":"cUj5","level":2,"heading":"Object Aliasing","content":"
Object Aliasing
\nThe ability for Python to assign multiple names to Python objects.\n\ne.g. Functions can be referenced through multiple names.\n\n\n\n"},{"id":"Vbeb","level":2,"heading":"Operators","content":"
Operators
\nA symbols takes one or two arguments and performs a calculation on them.\n\nExample: +, -, *, /\n\n\n\n"},{"id":"DnJ1","level":2,"heading":"Package","content":"
Package
\nGenerally a directory that contains module files and the file __info__.py (required).\n\nAll packages are modules but not all modules are packages.\n\n\n\n"},{"id":"xGGE","level":2,"heading":"Pass By Assignment","content":"
Pass By Assignment
\nPython passes arguments by assignment (object reference).\n\nAll variables are references(pointers) to an object. The references are copied in the arguments. Thus the function/method has access to the original value and mutable objects can be changed. However, reassign the variable ( var = …) and the reference to the original object is gone.\n\n\n\n"},{"id":"yNBJ","level":2,"heading":"PEP 8 - Style Guide","content":"
\nConverting an object hierarchy into a byte stream.\n\nUnpickling is the inverse operation converting a byte stream back into an object hierarchy.\n\n\n\n"},{"id":"MPqF","level":2,"heading":"Process","content":"
Process
\nA single execution unit executing a part of the program.\n\nProcesses run on their own python interpeter and have their own memory space. As a result, there are no issues with GIL and performance is improved. They are costly to start up (use Pool to get the startup hit only one time) but perform true multitasking.\n\nLibrary: multiprocessing\n\nSee Also: Multitasking, Threads\n\n\n\n"},{"id":"DV7Z","level":2,"heading":"PyPy","content":"
PyPy
\nAn alternative to the standard python language.\n\nFeatures: Just in time compiler, better memory management, Stackless.\nPyPy is written in RPython and compiled into c.\n\n\n\n"},{"id":"zZws","level":2,"heading":"Python Package Index (PiPy)","content":"
\nPython was created in 1991 by Guido van Rossum.\n\n\n\n"},{"id":"wEUB","level":2,"heading":"Raw String","content":"
Raw String
\nA string where values between the quotes are seet as in. No processing is done on the values between the quotes.\n\n\n\n"},{"id":"yRSy","level":2,"heading":"Read Eval Print Loop (REPL)","content":"
\nA strict subset of python that can be statically compiled into C.\n\n\n\n"},{"id":"VLxG","level":2,"heading":"Samples","content":"
Samples
\nCongratulations in testing out the -only feature. Here are your samples \uD83D\uDC4D\n\nNot happy with this? Let us know and we'll put something better in here.\n\n\n\n"},{"id":"K2P0","level":2,"heading":"self","content":"
self
\nA reference to the class instance.\n\nUse it to reference any instance variables or methods inside the class..\nMust be declared in every instance method in a class.\n\nSimilar to this in other languages.\n\n\nExample:\n\n
\nAny iterable type in Python.\n\nIncludes lists, sets, tuples, range, strings, etc.\n\n\n\n"},{"id":"Gw21","level":2,"heading":"Symbol Table","content":"
Symbol Table
\nA structure used by python to track and manage what program elements have been loaded and are are in scope.\n\n\n"},{"id":"MybA","level":3,"heading":"Global Symbol Table","content":"
Global Symbol Table
\nManages all program elements that are global.\n\nSee: globals()\n\n\n"},{"id":"ZnT6","level":3,"heading":"Local Symbol Table","content":"
Local Symbol Table
\nManages all program elements that are currently in local scope.\n\nSee: locals()\n\n\n\n"},{"id":"bg4Z","level":2,"heading":"Thread","content":"
Thread
\nA single execution unit executing a part of the program.\n\nThreads run in shared memory, on a single execution thread and use the same python interpreter. A thread needs to acquire GIL lock before it can execute. Threads are light weight to start up. Threads do not give an overall performance improvement as they use cooperative multitasking inside a single process.\n\nLibrary: threading\n\nSee Also: Multitasking, Process, GIL\n\n\n\n\n"},{"id":"3cTm","level":2,"heading":"Timestamp","content":"
Timestamp
\nThe number of seconds since January 1st, 1970 at 00:00:00 UTC.\n\nCan be an integer or float.\n\nAlso called Unix Time, Epoch Time.\n\n\n\n"},{"id":"DzTY","level":2,"heading":"Top Level Statement","content":"
Top Level Statement
\nStatements in a module (python file) that are outside functions and classes.\n\n\n\n"},{"id":"fHq5","level":2,"heading":"Tuple","content":"
\nAdded to Python 3.5, this allows you to label types in function signatures.\n\nhttps://docs.python.org/3/library/typing.html\n\n\n\n"},{"id":"Ywj7","level":2,"heading":"Venv / Virtual Environment","content":"
Venv / Virtual Environment
\nCreates an isolated python environment for a program to run in.\n\nShips standard with Python 3. It contains it's own packages independent of the global python environment but it links back to the standard python installation when possible. The environment must be accessed through a custom shell started up by one of the script files. Does not support Python 2.\n\nvs virtualenv\n\n\n\n"},{"id":"Hdpn","level":2,"heading":"VirtualEnv","content":"
VirtualEnv
\nA 3rd party tool used to create isolated Python environments.\n\nvirtualenv creates a directory which contains all the necessary executables to use the packages that a Python project would need. It works by installing required python files and binaries in a directory (eg: env/), and then modifying the PATH environment variable to prefix it with a custom bin directory (eg: env/bin/).\n\nPrefer venv.\n\n\n\n"},{"id":"v71r","level":2,"heading":"Wheel","content":"
Wheel
\nA packaging system used to distribute but not execute python files. It is preferred over egg files. Can be stored on PyPI servers.\n\nvs: Egg\n\n\n\n"},{"id":"SgBG","level":1,"heading":"Other SpeedSheets","content":"
\nThe aiohttp library for making asynchronous http calls.\n\nSheet:\taiohttp\n\n\n\n"},{"id":"nzUG","level":2,"heading":"BeautifulSoup SpeedSheet","content":"
BeautifulSoup SpeedSheet
\nAn easy to use library for processing HTML or XML.\n\nSheet:\tBeautifulSoup\n\n\n\n"},{"id":"gEx8","level":2,"heading":"Numpy SpeedSheet","content":"
Numpy SpeedSheet
\nA great library for manipulating large amounts of data.\n\nSheet:\tnumpy\n\n\n\n"},{"id":"C2gT","level":2,"heading":"Pandas SpeedSheet","content":"
Pandas SpeedSheet
\n\n⚠️ The Pandas SpeedSheet doesn't hava any content. Send us a note if you'd like to see this updated. Or contribute on Github.\n\nSheet: Pandas\n\nGit Source: https://github.com/speedsheet/sheet-python-pandas\n\n\n"},{"id":"MqsT","level":2,"heading":"Pillow SpeedSheet","content":"
\nThe requests library for making http calls.\n\nSheet:\trequests\n\n\n\n"},{"id":"zrnQ","level":1,"heading":"More Speedsheets?","content":"
More Speedsheets?
\n\nThis sheet covers core python only. But want to see more here? Or for other libraries? Please let us know.\n\nOr make contributions on Github:\nSpeedSheet Source on GitHub\n\n\n\n"},{"id":"wnL5","level":1,"heading":"Legal","content":"