[Python-Dev] cmp(x,x)
Tim Peters
tim.one at comcast.net
Tue May 18 14:37:31 EDT 2004
> >>> cmp(x,x) # x.__cmp__() is NOT called
> 0
[Gustavo Niemeyer]
> This is odd. We'll have problems trying to implemnt a NaN
> following the convention of being not-equal to itself,
> for example.
That's what rich comparisons are for. There's no problem getting
>>> x = some_nan
>>> x = x
False
>>>
in Python 2.4 (the result of that is *currently* a platform-dependent
crapshoot, though).
cmp(x, y) doesn't make sense for objects having only a partial ordering, so
I don't care cmp() does with a NaN.
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