[Python-Dev] Saving the hash value of tuples

Raymond Hettinger python at rcn.com
Mon Apr 3 05:23:58 CEST 2006


>> I've found out that the hash value of tuples isn't saved after it's
>> calculated. With strings it's different: the hash value of a string is
>> calculated only on the first call to hash(string), and saved in the
>> structure for future use. Saving the value makes dict lookup of tuples
>> an operation with an amortized cost of O(1).
>>  [...] 
>> I will be happy to send a patch, if someone shows interest.
> 
> Regardless of whether anyone shows interest, please submit a patch!  Then
> post the URL back here.  That way if someone gets interested in the
> future, your code is still available.

FWIW, I think that is not a good idea.  Guido shot it down for good reason.
Once a patch is loaded, the question will continually resurface every few
months and waste everyone's time re-hashing the issue.  We have bigger
dragons to slay.


Raymond


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