I won't speak for the IEEE but NOT A NUMBER does not tell you what something IS.
If "Hello, World!" is not a number as in an int or a float and we throw away the content and simply call it a NaN or something and then we notice that an object that is a list of fruits is also not a number so we call it a NaN too, then should they be equal? A NaN is a bit like a black hole. Anything thrown in disappears and that is about all we know about it. No two black holes are the same even if they seem to have the same mass, spin and charge. All they share is that we don't know what is in them. When variable "a" is a Nan then it is sort of a pointer to a concept. The pointer IS itself but the concepts may not be. -----Original Message----- From: Python-list <python-list-bounces+avigross=verizon....@python.org> On Behalf Of Grant Edwards Sent: Wednesday, February 13, 2019 1:03 PM To: python-list@python.org Subject: Re: Why float('Nan') == float('Nan') is False On 2019-02-13, ast <n...@gmail.com> wrote: > Hello > > >>> float('Nan') == float('Nan') > False If you think that's odd, how about this? >>> n = float('nan') >>> n nan >>> n is n True >>> n == n False >>> > Why ? IEEE says so. -- Grant Edwards grant.b.edwards Yow! Like I always say at -- nothing can beat gmail.com the BRATWURST here in DUSSELDORF!! -- https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list