What is the difference between decorators and annotations in programming?

What is the difference between decorators and annotations in programming?

Decorators are a design pattern in Python that allows you to modify the behavior of a function or class. Annotations, on the other hand, are a way to attach metadata to functions or variables, often used for type hints.

Can you give me an example of a decorator?

Sure! Here's a simple example of a decorator in Python:

def my_decorator(func):
    def wrapper():
        print("Something is happening before the function is called.")
        func()
        print("Something is happening after the function is called.")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")

say_hello()  # This will show the decorator in action.

What about annotations? How are they used?

Annotations in Python are used to provide hints about the types of function arguments and return values. For example:

def greet(name: str) -> str:
    return f"Hello, {name}!"

Here, name: str indicates that name should be a string, and -> str indicates that the function returns a string.

Are decorators and annotations used together?

Yes, they can be used together! You can use decorators to modify functions that also have type annotations, enhancing both functionality and clarity.