[Python-Dev] PyObject_RichCompareBool identity shortcut (original) (raw)

Stephen J. Turnbull stephen at xemacs.org
Thu Apr 28 04:31:20 CEST 2011

Glenn Linderman writes:

I would not, however expect the original case that was described:

nan = float('nan') nan == nan False [nan] == [nan] True # also True in tuples, dicts, etc.

Are you saying you would expect that

nan = float('nan') a = [1, ..., 499, nan, 501, ..., 999] # meta-ellipsis, not Ellipsis a == a False

??

I wouldn't even expect

a = [1, ..., 499, float('nan'), 501, ..., 999] b = [1, ..., 499, float('nan'), 501, ..., 999] a == b False

but I guess I have to live with that. While I wouldn't apply it to other people, I have to admit Raymond's aphorism applies to me (the surprising thing is not the behavior of NaNs, but that I'm surprised by anything that happens in the presence of NaNs!)

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