Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: Wolfgang Maier <wolfgang.maier@biologie.uni-freiburg.de>
Newsgroups: comp.lang.python
Subject: Re: static variables
Date: Tue, 1 Dec 2015 10:58:50 +0100
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On 01.12.2015 09:26, Ulli Horlacher wrote:
> Steven D'Aprano <steve@pearwood.info> wrote:
>
>> A better and more general test is:
>>
>> if hasattr(a, 'x'): print('attribute of a')
>
> Fine!
>
> I have now:
>
> def a(x=None):
>    if not hasattr(a,'x'): a.x = 0
>    a.x += 1
>    print('%d:' % a.x,x)
>
> This simply counts the calls of a()
>
> But, when I rename the function I have to rename the attribute also.
> Is it possible to refer the attribute automatically to its function?
> Something like:
>
> def a(x=None):
>    if not hasattr(_function_,'x'): _function_.x = 0
>    _function_.x += 1
>    print('%d:' % _function_.x,x)
>
>


I'm wondering whether you have a good reason to stick with a function. 
What you are trying to achieve seems to be easier and cleaner to 
implement as a class:

class Counter (object):
     def __init__ (self, start_value=0):
         self.x = start_value

     def __call__ (self):
         self.x += 1

1) solves the renaming problem
2) allows you to have several counters around:

counter1 = Counter()
counter2 = Counter()
counter3 = Counter(35)
counter1()
counter2()
counter1()
print (counter1.x, counter2.x, counter3.x)

Cheers,
Wolfgang