What are the best practices for using type annotations in Python?

What are the best practices for using type annotations in Python?

Using type annotations improves code readability and helps with static type checking. Here are some best practices:

1. Use clear and descriptive type names.
2. Annotate function parameters and return types.
3. Use Optional for nullable types.
4. Keep annotations consistent across your codebase.

Can you give me an example of a function with type annotations?

Sure! Here's a simple example:

def add_numbers(a: int, b: int) -> int:
    return a + b

This function takes two integers and returns their sum as an integer.

What if I want to annotate a list of strings?

You can use the List type from the typing module. For example:

from typing import List

def process_names(names: List[str]) -> None:
    for name in names:
        print(name)

This function takes a list of strings as input.

Are there any tools to help with type checking?

Yes! Tools like mypy and Pyright can help you perform static type checking in your Python code. They analyze your code and report type errors.