Functions

Decorators

Decorators wrap or register functions using @ syntax.

A decorator is just a function that takes a function and returns another callable. Applying it manually shows the wrapping step.

Source

from functools import wraps


def loud(func):
    @wraps(func)
    def wrapper(name):
        return func(name).upper()
    return wrapper


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

manual_greet = loud(greet)
print(manual_greet("python"))

Output

HELLO PYTHON

The @loud syntax performs the same rebinding at definition time. After decoration, welcome refers to the wrapper returned by loud.

Source

@loud
def welcome(name):
    """Return a welcome message."""
    return f"welcome {name}"

print(welcome("workers"))

Output

WELCOME WORKERS

functools.wraps copies useful metadata from the original function onto the wrapper.

Source

print(welcome.__name__)
print(welcome.__doc__)

Output

welcome
Return a welcome message.

Notes

@decorator is shorthand for assigning func = decorator(func).
Decorators can wrap, replace, or register functions.
Use functools.wraps in production wrappers that should preserve metadata.

Run the complete example

Expected output

HELLO PYTHON
WELCOME WORKERS
welcome

Execution time appears here after you run the example.

Decorators

See also

Run the complete example

Example code

Expected output