Lesson 38 / 49

Decorator Basics

Wrap functions with decorators to add behaviour without changing their code, using @ syntax and *args.

@decorator syntax

A decorator takes a function, returns a new wrapped function. @decorator above a def is shorthand for func = decorator(func).

def shout(func):
    def wrapper(*args, **kwargs):
        result = func(*args, **kwargs)
        return result.upper()
    return wrapper

@shout
def greet(name):
    return f"hello, {name}"

print(greet("ada"))   # HELLO, ADA

Wrapping, not changing

A decorator is like gift wrapping — the function inside is unchanged, but it now comes with extra behaviour around it.