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

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

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

1. Use type hints for function parameters and return types.
2. Prefer built-in types like int, str, and list over typing module types when possible.
3. Use Optional for parameters that can be None.
4. Be consistent in your type hinting style throughout your codebase.

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

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 should I do if I have complex data types?

For complex data types, you can use the typing module. For example, you can use List, Dict, or even create custom types with TypedDict or NamedTuple. Here's an example:

from typing import List, Dict

def process_data(data: List[Dict[str, int]]) -> None:
    pass

This function expects a list of dictionaries with string keys and integer values.

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 any type inconsistencies.