What are the best practices for using types in Python?

What are the best practices for using types in Python?

Using types in Python can enhance code readability and maintainability. Here are some best practices:

1. Use type hints to specify expected types for function parameters and return values.
2. Utilize the typing module for complex types like lists, dictionaries, and custom classes.
3. Keep type hints consistent across your codebase to avoid confusion.
4. Use type checkers like mypy to catch type errors before runtime.

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

Sure! Here's a simple example:

from typing import List

def greet_users(names: List[str]) -> None:
    for name in names:
        print(f'Hello, {name}!')

In this example, names is expected to be a list of strings, and the function returns nothing (None).

What about using types with classes?

When using types with classes, you can specify types for attributes and methods. For example:

class Person:
    def __init__(self, name: str, age: int) -> None:
        self.name = name
        self.age = age

    def greet(self) -> None:
        print(f'Hello, my name is {self.name} and I am {self.age} years old.')

Are there any downsides to using type hints?

While type hints improve code clarity, they can add verbosity and may require additional effort to maintain. However, the benefits often outweigh these downsides, especially in larger codebases.