How To Make A Simple Function Decorator (Python Recipes)

In this video I will be showing you how you can create a simple function decorator in Python! Decorators are some of Python's best sugar syntax which make applying extra functionality much more convenient.

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[aaronvegoda]

For anyone wondering how to fully type hint a decorator, here it is.

import functools
from typing import Callable, ParamSpec, TypeVar

P = ParamSpec("P")
T = TypeVar("T")

def time_func(func: Callable[P, T]) -> Callable[P, T]:
@functools.wraps(func)
def wrapper(*args: P.args, **kwargs: P.kwargs) -> T:
# code
result = func(*args, **kwargs)
# code
return result
return wrapper

What ParamSpec does, is it captures not only the exact signature of the callable, but the names of the args as well.

[obsidiansiriusblackheart]

You should do a pytest video using conftest and show how to mock a wrapped method (I did this recently at work, I'm a senior dev and it certainly wasn't easy just using docs/copilot lol)

[therealslimaddy]

Functools wraps solved my biggest problem(I was trying to apply two decorators).

Thanks for this!!

[ranjithkumars]

I always have a confusion with decorators, Thanks for this video❤

I cannot quite understand the super function can please explain it in the next video

[fire]

Is there a decorator that makes a functuon async? Without infecting all the functions that call it to be async aswell? Thanks

[danbromberg]

Good video but it'd be helpful if you either briefly summarized what a 'decorator' does or pointed to one of your earlier videos that discussed it.

[anon_y_mousse]

And here I was thinking a decorator in Python was a feather boa. ;)

[celestialowl]

Lambda and nested lambda decorators are novel but neat

[TristanM]

I heard also about decorators with parameters, but the way it's implemented looks dirty to me, so i prefer using functions composition/currying instead of decorators when it becomes more complex.

[ApprendreSansNecessite]

If you do this you totally loose the type signature of your function. It becomes `(...) -> Any`

[kundan.]

May someone tell me that which app is this?

[DrDeuteron]

I read a decorator is a macro, but it's written in python.