[Python-Dev] cpython: Describe the default hash correctly, and mark a couple of CPython (original) (raw)
Nick Coghlan ncoghlan at gmail.com
Sun May 20 12:58:02 CEST 2012
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On Sun, May 20, 2012 at 8:09 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
On Sun, 20 May 2012 10:31:01 +0200 nick.coghlan <python-checkins at python.org> wrote:
+ + .. impl-detail:: + + CPython uses
hash(id(x))as the default hash for class instances. This isn't true:class C: pass ... c = C() hash(c) 619973 id(c) 9919568 hash(id(c)) 9919568 id(...) always has the lower bits clear, so it was decided to shift it to the right by a number of bits.
Ah, you're right - I misread my own experiment. Regardless, the hash(c) == id(c) that was there was also wrong. I'll just drop the implementation detail entirely and leave the new wording on its own.
Cheers, Nick.
-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia
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