function decorator-like function

[Patrick Maupin]

On Mar 27, 10:24 am, vsoler <vicente.so... at gmail.com> wrote:
> Hi,
>
> Still learning Python, now decorators.
>
> Before diving deeply into decorators, I'd like to apply a function to
> another function.
>
> My "extremely simple function" should print number 3, then the sum of
> its 2 arguments.
>
> Say that I call   f(5,7)
> I'd like to get, somehow, 3 then 12.
>
> I've tried the following:
>
> def d(f):
>     print 3
>     return f
>
> def f(a, b):
>     print a+b
>
> f=d(f)
>
> However, it does not work. Calling f(5,7) only returns 12, (3 is
> missing)
> How should I proceed?

>>> def d(f):
...     def wrapper(*args):
...         print 3
...         return f(*args)
...     return wrapper
...
>>> def f(a, b):
...     print a + b
...
>>> f = d(f)
>>> f(5, 7)
3
12

HTH,
Pat