Python Cheat Sheet

Syntax/Concept	Example	Explanation
Print statement	print("Hello, world!")	Outputs the given text to the console
Comments	# 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.
""”
Variables	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
Loops	for, while	Statements used to iterate over a sequence of data
Functions	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
Classes	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,

  • Corey Schafer

Class

• 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:
    pass 

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

emp_2.first = 'Test'
emp_2.last = 'User'
emp_2.email = '[e-mail]'
emp_21.pay = '60000'
######

class Employee:
    def __init__(self,first,last,pay):
        #set instance variable 
        self.first = first
        self.last = last
        self.pay =pay
        self.email = first +'.' + last + '@company.com'
        
    # 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)

print(emp_1.email)
print(emp_2.email)

# running actions
    #manually 
    print('{}{}'.format)emp_1.first,emp_1,last))
    
    # better 
    print(emp_1.fullname()) # notice the parenthesis as it is a method

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