How can I use the typing module for advanced type hinting in Python?

How can I use the typing module for advanced type hinting in Python?

You can use the typing module to create complex type hints, such as using Union, Optional, and generics. Would you like examples?

Yes, please provide an example using Union and Optional.

Sure! You can define a function like this:

from typing import Union, Optional

def process_value(value: Union[int, str, None]) -> Optional[str]:
    if isinstance(value, int):
        return str(value)
    elif isinstance(value, str):
        return value.upper()
    return None

This function accepts an int, str, or None and returns an Optional str.

That's helpful! How do I use generics with the typing module?

You can define a generic type using TypeVar. For example:

from typing import TypeVar, List

T = TypeVar('T')

def get_first_element(elements: List[T]) -> T:
    return elements[0]

This function returns the first element of a list of any type.