[Python-ideas] checking for identity before comparing built-in objects

Guido van Rossum guido at python.org
Mon Oct 8 03:51:51 CEST 2012

On Sun, Oct 7, 2012 at 6:09 PM, Alexander Belopolsky
<alexander.belopolsky at gmail.com> wrote:
> On Sun, Oct 7, 2012 at 8:54 PM, Guido van Rossum <guido at python.org> wrote:
>> Seriously, we can't change our position on this topic now without
>> making a lot of people seriously unhappy. IEEE 754 it is.
> I did not suggest a change.  I wrote: "I am not suggesting any
> language changes, but I think it will be
> useful to explain why float('nan') != float('nan') somewhere in the
> docs."  If there is a concise explanation for the choice of IEEE 754
> vs. Java, I think we should write it down and put an end to this
> debate.

Referencing Java here is absurd and I still consider this suggestion
as a troll. Python is not in any way based on Java.

On the other hand referencing IEEE 754 makes all the sense in the
world, since every other aspect of Python float is based on IEEE 754
double whenever the underlying platform implements this standard --
and all modern CPUs do. I don't think there's anything else we need to

--Guido van Rossum (python.org/~guido)

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