What is a decorator in Python and what is it used for?

A decorator in Python is a function that takes another function and returns a new function with extended or modified behavior, without changing the source code of the decorated function.

Decorators are often used for:

• Logging function calls
• Access control checks
• Caching results
• Measuring execution time

An example of a simple decorator that prints a message before and after calling a function:

def my_decorator(func):
    def wrapper(*args, **kwargs):
        print("Before calling the function")
        result = func(*args, **kwargs)
        print("After calling the function")
        return result
    return wrapper

@my_decorator
def say_hello(name):
    print(f"Hello, {name}!")

say_hello("World")

Output:

Before calling the function
Hello, World!
After calling the function

Thus, decorators make it convenient and clean to add additional behavior to functions.