Python Cheat Sheet: A Quick Guide for Beginners

Whether you're a Python newbie or a seasoned dev needing a refresher, this cheat sheet has your back. It covers the essentials—variables, control flow, data structures, functions, and more—without any fluff. Let's dive in! 🚀

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📌 1. Basics

python
# Comments
print("Hello, Python!")  # This prints text

• Indentation matters (usually 4 spaces)

• Semicolons are optional—prefer one statement per line

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🔢 2. Data Types

python
x = 42          # int
pi = 3.14       # float
name = "Alice"  # str
active = True   # bool

• Use type() to check data type

• Strings are immutable, but lists are not

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📋 3. Variables & Operators

python
x += 1       # Same as x = x + 1

• Math: + - * / // % **

• Compare: == != > < >= <=

• Logic: and, or, not

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📦 4. Data Structures

Lists

python
nums = [1, 2, 3]
nums.append(4)

Tuples

python
t = (1, 2)

Sets

python
s = {1, 2, 2, 3}   # {1, 2, 3}

Dictionaries

python
person = {"name": "Bob", "age": 30}

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🔁 5. Control Flow

If-Else

python
if x > 0:
    print("Positive")
elif x == 0:
    print("Zero")
else:
    print("Negative")

Loops

python
for i in range(3):
    print(i)
while x > 0:
    x -= 1

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🧰 6. Functions

python
def greet(name):
    return f"Hello, {name}"

• Use return to return values

• Use *args, **kwargs for flexible arguments

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📂 7. File Handling

python
# Write
with open("file.txt", "w") as f:
    f.write("Hello!")
# Read
with open("file.txt", "r") as f:
    content = f.read()

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🚨 8. Error Handling

python
try:
    1 / 0
except ZeroDivisionError:
    print("Oops!")
finally:
    print("Always runs")

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🧪 9. Built-In Functions

• len(), type(), str(), int(), float()

• sum(), min(), max(), sorted()

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🔍 10. Importing Modules

python
import math
math.sqrt(25)  # 5.0
from random import choice
choice(["A", "B", "C"])

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📎 Final Thoughts

Python is elegant, versatile, and beginner-friendly. This cheat sheet is just the beginning—explore libraries like pandas, flask, or pygame as you grow.

👉 Bookmark this page for quick reference, and happy coding!