๐ Python Type Hints โ Write Safer, Self-Documenting Code
Type hints make Python code more readable, catch bugs earlier, and supercharge IDE autocomplete. Introduced in Python 3.5, improved in every version since.
๐ก Quick Tip:
Run mypy or pyright on your codebase to catch type errors before runtime. VS Code's Pylance does this automatically.
๐ป Code Example:
from typing import Optional, Union, List, Dict, Any from dataclasses import dataclass # 1. Basic type annotations def calculate_discount(price: float, discount_pct: float) -> float: return price * (1 - discount_pct / 100) result: float = calculate_discount(999.0, 10) # 899.1 # 2. Optional โ can be None def find_user(user_id: int) -> Optional[Dict[str, Any]]: users = {42: {'name': 'santoshtvk', 'platform': 'pynfinity'}} return users.get(user_id) # Returns dict or None # 3. Union โ accept multiple types (Python 3.10+ use X | Y) def process_score(score: Union[int, float]) -> str: return f"Score: {score:.1f}%" # Python 3.10+ cleaner syntax: def process_score_modern(score: int | float) -> str: return f"Score: {score:.1f}%" # 4. Typed dataclass โ best of both worlds @dataclass class PynfinityUser: name: str score: float = 0.0 is_premium: bool = False courses: List[str] = None def __post_init__(self): if self.courses is None: self.courses = [] user = PynfinityUser(name="dhruv", score=95.5) print(user) # PynfinityUser(name='dhruv', score=95.5, is_premium=False, courses=[])
| Concept | Key Takeaway |
|---|---|
| Optional[X] | X or None โ same as Union[X, None] |
| Union[X, Y] | Accepts X or Y (use X | Y in Python 3.10+) |
| List[str] | A list containing strings |
| Dict[str, int] | A dict with str keys and int values |
| Any | No constraint โ disables type checking for that value |
Keep exploring and happy coding! ๐
