Python Cheat Sheet


Print statement

print("Hello, world!")

Outputs the given text to the console


# This is a comment

Comments are ignored by Python and are used to document code

Multiline comment


This is a multiline comment.

It can span multiple lines without the need for multiple comment symbols.

You can use it to document your code or temporarily disable a block of code.



x = 5

Variables are used to store data and can be assigned and reassigned values

Data types

int, float, string, bool, list, tuple, dict, set

Different types of data that can be stored in variables

Numeric operations

+, -, *, /, %, **

Operators used for arithmetic operations

Comparison operators

==, !=, >, <, >=, <=

Operators used to compare values

Logical operators

and, or, not

Operators used to combine and manipulate boolean values

Conditional statements

if, elif, else

Statements used to conditionally execute code


for, while

Statements used to iterate over a sequence of data


def my_func():, return

Blocks of code that can be called and returned

Lambda functions

lambda x: x + 1

Anonymous functions used for simple operations


class MyClass:, def init(self):, self

Used to define custom data types and associated functions

List methods

append(), extend(), insert(), remove(), pop(), index(), count(), sort(), reverse()

Methods used to manipulate lists

Tuple methods

count(), index()

Methods used to manipulate tuples

Dictionary methods

keys(), values(), items(), get(), update(), pop(), popitem(), clear()

Methods used to manipulate dictionaries

Set methods

add(), remove(), discard(), pop(), clear(), union(), intersection(), difference(), symmetric_difference()

Methods used to manipulate sets

Getting Started

  • Corey Schafer, Object-Oriented Programming 6 parts

  • Setting up a Python Development Environment

    • Requirements: syntax highlighting, beautification, linter, IntelliSense: list members, parameter info, quick info, autocompletion,


  • Why? Logically group our data and functions that we can easily reuse or build upon

  • Terminology

    • Attributes and methods - functions that is associated with class

    • A class is a blueprint for creating instances

class Employee:

# instances of a Employee classes
emp_1 = Employee()
emp_2 = Employee()
# unique data 
#manually variable setting - prone to human error
emp_1.first = 'Corey'
emp_1.last = 'Scafer' = '' = '50000'

emp_2.first = 'Test'
emp_2.last = 'User' = '' = '60000'

class Employee:
    def __init__(self,first,last,pay):
        #set instance variable 
        self.first = first
        self.last = last =pay = first +'.' + last + ''
    # each method within a class automatically takes the insance as the first argument
    # and we always call that self
    def fullname(self)
        return '{}{}'.format(self.first,self.last)
# better solution: runs init automatically 
emp_1 = Employee('Corey','Scafer',50000)
emp_2 = Employee('Test','User',60000)


# running actions
    # better 
    print(emp_1.fullname()) # notice the parenthesis as it is a method

#classes are kinda like function
# remember to put self in methods in class
    emp_1.fullname() is same as Employee.fullname(emp_1))

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