[Python-Dev] PyObject_RichCompareBool identity shortcut

[Stephen J. Turnbull]

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.<wink>  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!)