What are the best practices for using annotations in Python?

What are the best practices for using annotations in Python?

Using annotations in Python can enhance code readability and maintainability. Best practices include using type hints for function parameters and return types, keeping annotations simple and clear, and using the Optional type for nullable values.

Can you give me an example of how to use type hints?

Sure! Here's a simple example:

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

In this function, a and b are annotated as integers, and the return type is also an integer.

What about complex data types like lists or dictionaries?

For complex data types, you can use the List and Dict from the typing module. For example:

from typing import List, Dict

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

This indicates that data is a list of dictionaries with string keys and integer values.

Are there any tools to help with type checking?

Yes! Tools like mypy can be used to perform static type checking in your Python code. It helps catch type errors before runtime.