[Tutor] recursive problem

[Luke Paireepinart]

Nope Joel, that's what I meant. Remember EAFP over LBYL! I'm not sure the best way to make sure the object is iterable though.

Sent from my iPhone

On Sep 9, 2010, at 11:41 AM, Joel Goldstick <joel.goldstick at gmail.com> wrote:

> 
> 
> On Thu, Sep 9, 2010 at 12:07 PM, Steven D'Aprano <steve at pearwood.info> wrote:
> On Fri, 10 Sep 2010 01:05:22 am Joel Goldstick wrote:
> > On Thu, Sep 9, 2010 at 10:26 AM, Luke Paireepinart
> >
> > <rabidpoobear at gmail.com>wrote:
> > > Shouldn't there be a way to do this without type checking? Duck
> > > typing!
> > >
> > > Your post got me thinking.  Maybe better to test if the object can
> > > return
> > an iter method.  If it throws an error, then look at its value.  If
> > it doesn't, then its a list or a tuple
> 
> 
> It's not clear what you mean by "return an iter method". Taken
> literally, that would imply the object is a function. I think you
> mean "*has* an iter method" -- except that's not right either:
> 
> >>> [].iter
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> AttributeError: 'list' object has no attribute 'iter'
> 
> 
> Perhaps you mean an object which can be passed to iter(), but lots of
> objects can do that, not just lists and tuples:
> 
> >>> iter("not a list or tuple")
> <str_iterator object at 0xb7d3520c>
> >>> iter({1: None, 2: "a", 4: 5})
> <dict_keyiterator object at 0xb7d3420c>
> 
> 
> I was googling, and found that if an object has an __iter__ method it will return it.  If not it will throw an error.  You are right about more than lists and tuples being iterable.  But, in this thread, it was brought up that checking type may not be pythonic.  If you wanted to use the same code to find values in a nested list of any objects, you could dispense with the type checking and just see if it is iterable.
> 
> I'm new to python.  Am I off base? 
> 
> 
> --
> Steven D'Aprano
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor
> 
> 
> 
> -- 
> Joel Goldstick
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/tutor/attachments/20100909/73e3c886/attachment.html>