Type Annotations and Generics
Improve code clarity, IDE autocompletion, and maintainability with static type annotations.
Learning objectives
- Annotate function signatures with parameters and return types
- Use Union, Optional, List, Dict, and TypedDict
Lesson material
Type Hints Syntax
Type hints do not affect runtime execution directly, but enable static analysis tools like mypy.
Example code
from typing import List, Optional
def process_scores(scores: List[float]) -> Optional[float]:
if not scores:
return None
return sum(scores) / len(scores)
print("Average:", process_scores([90.0, 80.0, 100.0]))Practice exercise: Annotate Function
Define a function `greet_user(name: str, age: int) -> str` returning `f"{name} is {age}"`. Print `greet_user("Sam", 30)`.
Test yourself with the Module 16: Type Hints & Static Analysis quiz →