En Tue, 03 Jun 2008 17:11:06 -0300, Matthew Wilson <[EMAIL PROTECTED]>
escribió:
I used defaultdict.fromkeys to make a new defaultdict instance, but I
was surprised by behavior:
>>> b = defaultdict.fromkeys(['x', 'y'], list)
>>> b
defaultdict(None, {'y': <type 'list'>, 'x': <type 'list'>})
>>> b['x']
<type 'list'>
>>> b['z']
------------------------------------------------------------
Traceback (most recent call last):
File "<ipython console>", line 1, in <module>
KeyError: 'z'
I think that what is really going on is that fromdict makes a regular
dictionary, and then hands it off to the defaultdict class.
I find this confusing, because now I have a defaultdict that raises a
KeyError.
Do other people find this intuitive?
Would it be better if defaultdict.fromkeys raised a
NotImplementedException?
Or would it be better to redefine how defaultdict.fromkeys works, so
that it first creates the defaultdict, and then goes through the keys?
That looks reasonable. It appears there is currently no way to do what you
want (apart from using a for loop to set each key)
--
Gabriel Genellina
--
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