What are some examples of type hints in Python?

What are some examples of type hints in Python?

Type hints in Python are a way to indicate the expected data types of variables, function parameters, and return values. For example:

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

This function specifies that both a and b should be integers and that the return value will also be an integer.

Can you show me more complex examples?

Sure! Here's a more complex example using lists and dictionaries:

from typing import List, Dict

def get_user_info(user_id: int) -> Dict[str, List[str]]:
    # Simulated database query
    return {'user_id': [str(user_id)], 'roles': ['admin', 'editor']}

This function returns a dictionary where the keys are strings and the values are lists of strings.

What about using type hints with classes?

Great question! Here's an example with a class:

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

    def greet(self) -> str:
        return f'Hello, my name is {self.name} and I am {self.age} years old.'

In this class, the constructor and method both use type hints to specify the types of parameters and return values.