What are some examples of type annotation in Python?

What are some examples of type annotation in Python?

Type annotations in Python allow you to specify the expected data types of variables. For example:

1. def add(a: int, b: int) -> int: - This function takes two integers and returns an integer.
2. name: str = 'Alice' - This variable is annotated to be a string.
3. def greet(name: str) -> None: - This function takes a string and returns nothing.

Can you explain why type annotations are useful?

Type annotations help with code readability and maintainability. They allow developers to understand what types of arguments a function expects and what it returns, which can prevent bugs and improve collaboration.

Are there any tools that can help with type checking in Python?

Yes, tools like mypy can be used for static type checking in Python. They analyze your code and check for type inconsistencies based on the annotations you provide.

Can I use type annotations with lists and dictionaries?

Absolutely! You can use type annotations with collections. For example:

• from typing import List, Dict
• def process_items(items: List[int]) -> None: - This function takes a list of integers.
• def get_user_info() -> Dict[str, str]: - This function returns a dictionary with string keys and values.