[Python-3000] Default factory that uses key
Georg Brandl
g.brandl at gmx.net
Sun Jan 6 11:07:40 CET 2008
hashcollision schrieb:
> The default factory that collections.defaultdict takes cannot use key.
> Is there a way to have the default factory take the key into
> consideration? For example
>
> d = collections.defaultdict(lambda title: BookShelf(title))
>
> If not, I propose that it be added.
Note that you can easily write a type like that yourself, using
dict.__missing__:
class DefShelfDict(dict):
def __missing__(self, key):
shelf = self[key] = BookShelf(key)
return shelf
or some such.
Georg
--
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Four shall be the number of spaces thou shalt indent, and the number of thy
indenting shall be four. Eight shalt thou not indent, nor either indent thou
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