[Python-Dev] Python's C interface for types (original) (raw)

Giovanni Bajo rasky at develer.com
Fri Jan 26 20:27:14 CET 2007

On 26/01/2007 17.03, Thomas Wouters wrote:

How critical is the 'numeric' property of the nbhash function? I can certainly honour it, but is it worth it?

[...] There's no strict requirement that equal objects must have equal hashes,

Uh? I thought that was the only strict requirement of hash. In fact the docs agree:

==================================================== hash( self)

Called for the key object for dictionary operations, and by the built-in function hash(). Should return a 32-bit integer usable as a hash value for dictionary operations. The only required property is that objects which compare equal have the same hash value; [...]

I personally consider very important that hash(5.0) == hash(5) (and that 5.0 == 5, of course).

Giovanni Bajo

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