[Python-Dev] Tuning Python dicts (original) (raw)

Terry Reedy tjreedy at udel.edu
Sun Apr 11 03:19:43 CEST 2010

I may be missing the point, but ISTM that the assumption of this approach is that there are often collisions in the hash table. I think that assumption is false; at least, I recommend to validate that assumption before proceeding. It's just an experiment for a class, not something I am (yet) seriously thinking about contributing back to CPython. I think my chances of improving over the current implementation are slim. I do not have that much hubris. :) I would just rather do experimental rather than theoretical work with data structures. I think you're right about the number of collisions, though. CPython dicts use a pretty low load factor (2/3) to keep collision counts down.

There was a paper discussing Python dicts at PyCon 2010. I believe it included some data on collisions. I posted the link on Python list a couple of weeks ago.

Terry Jan Reedy

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