cheetsheetz/python.md

Python Cheat Sheet

Variables and Data Types

Variables

Declaring a variable

x = 5

Reassigning a variable

x = 10

Data Types

Integer

x = 5

Float

x = 5.0

Boolean

x = True

String

x = "Hello, World!"

Operators

Arithmetic Operators

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

Comparison Operators

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

Logical Operators

and, or, not

Control Structures

Conditional Statements

If statement

if x > 5: print("x is greater than 5") elif x == 5: print("x is equal to 5") else: print("x is less than 5")

Loops

For loop

for i in range(0, 5): print(i)

While loop

i = 0 while i < 5: print(i) i += 1

Functions

Defining a function

def my_function(param1, param2): print(param1 + param2)

Calling a function

my_function(5, 10)

Lists

Declaring a list

my_list = [1, 2, 3, 4, 5]

Accessing elements of a list

my_list[0] # returns 1 my_list[-1] # returns 5

Slicing a list

my_list[1:3] # returns [2, 3]

Appending to a list

my_list.append(6)

Removing from a list

my_list.remove(2)

Dictionaries

Declaring a dictionary

my_dict = {"key1": "value1", "key2": "value2"}

Accessing elements of a dictionary

my_dict["key1"] # returns "value1"

Adding to a dictionary

my_dict["key3"] = "value3"

Removing from a dictionary

del my_dict["key2"]

Classes

Declaring a class

class MyClass: def init(self, param1, param2): self.param1 = param1 self.param2 = param2

def my_method(self):
    print(self.param1 + self.param2)

Creating an instance of a class

my_instance = MyClass(5, 10)

Calling a method of a class

my_instance.my_method()

Exceptions

Catching an exception

try: # some code that may raise an exception except ExceptionType: # do something to handle the exception

Raising an exception

raise ExceptionType("Error message")