[Python-Dev] Proposal: defaultdict (original) (raw)

Raymond Hettinger raymond.hettinger at verizon.net
Sun Feb 19 08:11:33 CET 2006

[Terry Reedy]

One is a 'universal dict' that maps every key to something -- the default if nothing else. That should not have the default ever explicitly entered. Udict.keys() should only give the keys not mapped to the universal value.

Would you consider it a mapping invariant that "k in dd" implies "k in dd.keys()"?

Is the notion of contains at odds with notion of universality?

Raymond

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