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On Sun, 30 May 2010 03:27:53 +0000 (UTC) Benjamin Peterson <benjamin@python.org> wrote:
In the spirit of collections.OrderedDict and collections.defaultdict, I'd like to propose collections.identitydict. It would function just like a normal dictionary, but ignore hash values and comparison operators and merely lookup keys based on the key's id().
Perhaps it would be more useful to add a generic collections.keyfuncdict, taking a function which applied to a key gives the real key value used for lookups. Your identity dict would be created as: d = collections.keyfuncdict(id) But of course, you can just use a normal dict: d = {} d[id(key)] = key, value (actually, this could be how a collections.keyfuncdict gets implemented) Regards Antoine.