Python Syntax Cheat Sheet

Posted : admin On 1/29/2022

Python programming cheat sheet. Useful reference for beginners. Covers syntax, terminology, and more. Python supports the joining (concatenation) of strings together using the + operator. The + operator is also used for mathematical addition operations. If the parameters passed to the + operator are strings, then concatenation will be performed. If the parameter passed to + have different. Python Tutorial & Cheat Sheet. Getting Started What you need: Linux based machine with Python 2.7 or higher (comes default on most linux systems) (Python on windows also works though not ideal) Editor on Linux such as VI or EMACS to edit your files.

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Python Cheat Sheet Pdf

Cheat sheets can be really helpful when you’re trying a set of exercises related to a specific topic, or working on a project. Because you can only fit so much information on a single sheet of paper, most cheat sheets are a simple listing of syntax rules. This set of cheat sheets aims to remind you of syntax rules, but also remind you of important concepts as well. You can click here and download all of the original cheat sheets in a single document.

An updated version of these sheets is also available through Leanpub and Gumroad. The updated version includes a sheet that focuses on Git basics, a printer-friendly b&w version of each sheet, and each sheet as a separate document. The updated versions are available at no cost on both platforms.

Individual Sheet Descriptions

  • Beginner’s Python Cheat Sheet
    • Provides an overview of the basics of Python including variables, lists, dictionaries, functions, classes, and more.
  • Beginner’s Python Cheat Sheet - Lists
    • Focuses on lists: how to build and modify a list, access elements from a list, and loop through the values in a list. Also covers numerical lists, list comprehensions, tuples, and more.
  • Beginner’s Python Cheat Sheet - Dictionaries
    • Focuses on dictionaries: how to build and modify a dictionary, access the information in a dictionary, and loop through dictionaries in a variety of ways. Includes sections on nesting lists and dictionaries, using an OrderedDict and more.
  • Beginner’s Python Cheat Sheet - If Statements and While Loops
    • Focuses on if statements and while loops: how to write conditional tests with strings and numerical data, how to write simple and complex if statements, and how to accept user input. Also covers a variety of approaches to using while loops.
  • Beginner’s Python Cheat Sheet - Functions
    • Focuses on functions: how to define a function and how to pass information to a function. Covers positional and keyword arguments, return values, passing lists, using modules, and more.
  • Beginner’s Python Cheat Sheet - Classes
    • Focuses on classes: how to define and use a class. Covers attributes and methods, inheritance and importing, and more.
  • Beginner’s Python Cheat Sheet - Files and Exceptions
    • Focuses on working with files, and using exceptions to handle errors that might arise as your programs run. Covers reading and writing to files, try-except-else blocks, and storing data using the json module.
  • Beginner’s Python Cheat Sheet - Testing Your Code
    • Focuses on unit tests and test cases. How to test a function, and how to test a class.
  • Beginner’s Python Cheat Sheet - Pygame
    • Focuses on creating games with Pygame. Creating a game window, rect objects, images, responding to keyboard and mouse input, groups, detecting collisions between game elements, and rendering text.
  • Beginner’s Python Cheat Sheet - matplotlib
    • Focuses on creating visualizations with matplotlib. Making line graphs and scatter plots, customizing plots, making multiple plots, and working with time-based data.
  • Beginner’s Python Cheat Sheet - Pygal
    • Focuses on creating visualizations with Pygal. Making line graphs, scatter plots, and bar graphs, styling plots, making multiple plots, and working with global datasets.
  • Beginner’s Python Cheat Sheet - Django
    • Focuses on creating web apps with Django. Installing Django and starting a project, working with models, building a home page, using templates, using data, and making user accounts.

Available from No Starch Press and Amazon.

Basics

Print a number print(123)
Print a string print('test')
Adding numbers print(1+2)
Variable assignment number = 123
Print a variable print(number)
Function call x = min(1, 2)
Comment # a comment
Python 2.7 syntax cheat sheet

Types

Integer 42
String 'a string'
List [1, 2, 3]
Tuple (1, 2, 3)
Boolean True

Useful functions

Write to the screen print('hi')
Calculate lengthlen('test')
Minimum of numbersmin(1, 2)
Maximum of numbersmax(1, 2)
Cast to integerint('123')
Cast to stringstr(123)
Cast to booleanbool(1)
Range of numbersrange(5, 10)

Python Syntax Cheat Sheet Reddit

Other syntax

Return a value return 123
Indexing 'test'[0]
Slicing 'test'[1:3]
Continue to next loop iteration continue
Exit the loop break
List append numbers = numbers + [4]
List append (with method call) numbers.append(4)
List item extraction value = numbers[0]
List item assignment numbers[0] = 123

Terminology

syntax the arrangement of letters and symbols in code
program a series of instructions for the computer
print write text to the screen
string a sequence of letters surrounded by quotes
variable a storage space for values
value examples: a string, an integer, a boolean
assignment using = to put a value into a variable
function a machine you put values into and values come out
call (a function) to run the code of the function
argument the input to a function call
parameter the input to a function definition
return value the value that is sent out of a function
conditional an instruction that's only run if a condition holds
loop a way to repeatedly run instructions
list a type of value that holds other values
tuple like a list, but cannot be changed
indexing extracting one element at a certain position
slicing extracting some elements in a row
dictionary a mapping from keys to values

Reminders

Python Syntax Cheat Sheet
  • Strings and lists are indexed starting at 0, not 1
  • Print and return are not the same concept
  • The return keyword is only valid inside functions
  • Strings must be surrounded by quotes
  • You cannot put spaces in variable or function names
  • You cannot add strings and integers without casting
  • Consistent indentation matters
  • Use a colon when writing conditionals, function definitions, and loops
  • Descriptive variable names help you understand your code better

Conditionals

Lists

Defining functions

Loops

CheatPython commands

Dictionaries

Comparisons

Equals
Not equals !=
Less than <
Less than or equal <=
Greater than >

Useful methods

Python Syntax Cheat Sheet Pdf

String to lowercase 'xx'.lower()
String to uppercase 'xx'.upper()
Split string by spaces 'a b c'.split(' ')
Remove whitespace around string ' a string '.strip()
Combine strings into one string ' '.join(['a', 'b'])
String starts with 'xx'.startswith('x')
String ends with 'xx'.endswith('x')
List count [1, 2].count(2)
List remove [1, 2].remove(2)
Dictionary keys {1: 2}.keys()
Dictionary values {1: 2}.values()
Dictionary key/value pairs {1: 2}.items()

Python 3 6 Syntax Cheat Sheet

Other neat bonus stuff

Zip lists zip([1, 2], ['one', 'two'])
Set my_set = {1, 2, 3}
Set intersection {1, 2} & {2, 3}
Set union {1, 2} {2, 3}
Index of list element [1, 2, 3].index(2)
Sort a list numbers.sort()
Reverse a list numbers.reverse()
Sum of list sum([1, 2, 3])
Numbering of list elements for i, item in enumerate(items):
Read a file line by line for line in open('file.txt'):
Read file contents contents = open('file.txt').read()
Random number between 1 and 10 import random; x = random.randint(1, 10)
List comprehensions [x+1 for x in numbers]
Check if any condition holds any([True, False])
Check if all conditions hold all([True, False])

Python Syntax Cheat Sheet Pdf

Python

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