The Complete Guide to Python¶

Python is the most popular programming language. Here is a complete guide.

Basics¶

Variables, types¶

name = “Python” version = 3.12 features = [“simple”, “powerful”, “readable”] config = {“debug”: True, “port”: 8080}

Functions¶

def greet(name: str, greeting: str = “Hello”) -> str: return f”{greeting}, {name}!”

Lambda¶

square = lambda x: x ** 2

OOP¶

from dataclasses import dataclass

@dataclass class User: name: str email: str active: bool = True

List Comprehensions¶

squares = [x**2 for x in range(10)] evens = [x for x in range(100) if x % 2 == 0] flat = [item for sublist in nested for item in sublist]

Generators¶

def fibonacci(): a, b = 0, 1 while True: yield a a, b = b, a + b

Context Managers¶

with open(“file.txt”) as f: content = f.read()

Async¶

import asyncio

async def fetch(url): async with aiohttp.ClientSession() as session: async with session.get(url) as resp: return await resp.json()

Virtual Environment¶

python -m venv .venv source .venv/bin/activate pip install -r requirements.txt pip freeze > requirements.txt

Type Hints¶

from typing import Optional

def process(data: list[dict], limit: Optional[int] = None) -> list[str]: …

Tools¶

• uv/pip — package management
• ruff — linting + formatting
• mypy — type checking
• pytest — testing
• poetry/uv — dependency management

Tip¶

Python is easy to learn, hard to master. Focus on idiomatic Python — not just “working” code.