variable & scoping question.

Francesco Bochicchio bieffe62 at gmail.com
Mon Aug 10 17:36:52 CEST 2009


On Aug 10, 5:12 pm, "Diez B. Roggisch" <de... at nospam.web.de> wrote:
> Cornelius Keller wrote:
> > Hi,
>
> > I'm a quite fresh python programmer, (6 Month python experience).
> > Today I found something I absolotly don'nt understand:
>
> > given the following function:
>
> > def test_effect(class_id=None,class_ids=[]):
> >     if class_id is not None:
> >         if class_id not in class_ids:
> >             class_ids.append(int(class_id))
>
> >     print class_ids
>
> > I observe that the class_ids array is growing when it is called with
> > different class id's.
>
> > I expected class_ids to be [] if the keyword argument is not set, but
> > it seems to beahve like a static variable if not set.
>
> http://effbot.org/zone/default-values.htm
>
> Diez

Maybe on the first page of python.org there should be a 'python
gotchas' link to a page listing these few
non-intuituive peculiarities of our beloved snake ... same goes for
the official python tutorial ...

Ciao
-----
FB




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