Question

def foo():
    pass

def bar():
    print 'good bay'

two function like blow
and now i want to run bar function after foo run finish

is there some method like class use __del__?
as i know in class method i can use __del__ like follow:

 class A(object):
    def __init__(self):
        pass
    def __del__(self):
        bar()

but i can’t use foo.__del__
is there any other method to do this ?

Answer 1

This is what decorators are for. This decorator, used on foo with bar as an argument will will run bar after foo and still return foos result. It will work on functions with any number of arguments.

def run_before(lastfunc, *args1, **kwargs1):
    def run(func):
        def wrapped_func(*args, **kwargs):
            try:
                result = func(*args, **kwargs)
            except:
                result = None
            finally:
                lastfunc(*args1, **kwargs1)
                return result
        return wrapped_func
    return run

def bar():
    print 'goodby'

@run_before(bar)
def foo():
    print "hello"

foo()

Edit: Added error handling. Thanks @Björn