dictionary keys, __hash__, __cmp__

Jan-Erik Meyer-Lütgens python at meyer-luetgens.de
Wed Nov 5 15:03:19 CET 2003

Michael Hudson wrote:
> Jan-Erik Meyer-Lütgens  <python at meyer-luetgens.de> writes:
>>    3. "If a class does not define a __cmp__() method it
>>        should not define a __hash__() operation either."
>>Can I asume that:
>>  -- I can savely ignore the 3rd statement, because python
>>     falls back to cmp(id(obj1), id(obj2)), if __cmp__()
>>     is not defined.
> Don't understand.

Ok, let me ask the following question: What is the reason
for that rule?


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