Type Hints & Annotations — Free Python Tutorial

TL;DR: Learn Type Hints & Annotations in Python with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Type Hints & Annotations in Python

Type hints tell Python (and your editor) what type of data a variable or function expects and returns. They don't enforce types at runtime — they are for documentation and static analysis tools.

Basic hints: int, str, float, bool, list, dict. From typing module: List[int], Dict[str, int], Optional[str] (can be str or None), Union[int, str].

Python 3.10+ allows str | None instead of Optional[str]. Python 3.9+ allows list[int] instead of List[int] (no typing import needed).

Tools like mypy and pyright check type hints statically. IDEs like VS Code use them for autocomplete. Type hints make large codebases much easier to maintain.

from typing import Optional, Union, List, Dict, Tuple

def greet(name: str) -> str:
    return f"Hello, {name}"

def process(data: List[int]) -> Dict[str, int]:
    ...

def find(name: str) -> Optional[str]:  # can return None
    ...

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