Python Cheat Sheet
Python Cheat Sheet
Basic Syntax
# Comments
# This is a comment
# Variables
x = 5
name = "Alice"
# Data Types
integer = 10
float_num = 10.5
string = "Hello"
boolean = True
list_example = [1, 2, 3]
tuple_example = (1, 2, 3)
dict_example = {"key": "value"}
Control Structures
# If Statements
if x > 0:
print("Positive")
elif x < 0:
print("Negative")
else:
print("Zero")
# Loops
# For Loop
for i in range(5):
print(i)
# While Loop
while x < 5:
x += 1
Functions
# Defining Functions
def my_function(param1, param2):
return param1 + param2
# Lambda Functions
square = lambda x: x ** 2
Data Structures
# Lists
my_list = [1, 2, 3]
my_list.append(4)
# Dictionaries
my_dict = {"name": "Alice", "age": 25}
age = my_dict["age"]
# Sets
my_set = {1, 2, 3}
my_set.add(4)
# Tuples
my_tuple = (1, 2, 3)
List Comprehensions
squares = [x ** 2 for x in range(10)]
String Methods
# Common Methods
my_string = "Hello, World!"
my_string.lower()
my_string.upper()
my_string.split(", ")
File Handling
# Reading a File
with open('file.txt', 'r') as file:
content = file.read()
# Writing to a File
with open('file.txt', 'w') as file:
file.write("Hello, World!")
Exception Handling
try:
# Code that may raise an exception
result = 10 / 0
except ZeroDivisionError:
print("You can't divide by zero!")
finally:
print("This will always execute.")
Modules and Packages
# Importing Modules
import math
from datetime import datetime
Decorators
def my_decorator(func):
def wrapper():
print("Before the function.")
func()
print("After the function.")
return wrapper
@my_decorator
def say_hello():
print("Hello!")
Generators
def countdown(n):
while n > 0:
yield n
n -= 1
for number in countdown(5):
print(number)
Common Built-in Functions
# len(), sum(), max(), min(), sorted(), enumerate()
Useful Libraries
# NumPy, Pandas, Matplotlib, Requests, Flask/Django
Common Commands
# Install a Package
pip install package_name
# Run a Python Script
python script.py
