Description

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Advanced · 14 min

Decorators

Wrap a function to add behavior without changing its body.

Return a wrapper

A decorator receives a function and returns a replacement function. The wrapper can act before and after the original call.

def announce(function):
    def wrapper():
        print("Start")
        function()
    return wrapper

@announce
def work():
    print("Working")

work()

Output

Start
Working

Forward arguments

*args and **kwargs let a wrapper pass positional and keyword arguments to the wrapped function.

def double_result(function):
    def wrapper(*args, **kwargs):
        return function(*args, **kwargs) * 2
    return wrapper

@double_result
def add(a, b):
    return a + b

print(add(2, 3))

Output

10

Decorators

  1. Read both decorators examples before answering.
  2. Run the task, compare its exact output, and revise the code if needed.

Try it yourself

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Normalize a result

Complete uppercase_result so the decorated greet function returns HELLO, ADA. Keep the supplied call.

Practice