On Wed, 2006-03-29 at 00:15 -0500, Michael Broe wrote:
> Aha! John wrote:
>
> "Are you sure you haven't mistakenly assigned something other than a
> dict to D or D['d'] ?"
>
> Thanks for the tip! Yup that was it (and apologies for not reporting
> the problem more precisely). I hadn't initialized the nested
> dictionary before trying to assign to it. (I think Perl doesn't
> require initialization of dictionaries prior to assignment, which in
> this case, would be a nice thing...)
>
> >>> D['c']['a'] = 1 #ooops
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> KeyError: 'c'
> >>> D['c'] = {}
> >>> D['c']['a'] = 1
> >>> D
> {'a': {'a': 1, 'b': 2}, 'c': {'a': 1}}
>
You can check if the dictionary key exists prior to assigning to it:
>>> if not D.has_key('c'):
... D['c'] = {}
>>> D['c']['a'] = 1
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
