[Python-Dev] Why is nan != nan?
robert.kern at gmail.com
Sun Mar 28 01:27:57 CET 2010
On 2010-03-27 13:36 , Adam Olsen wrote:
> On Fri, Mar 26, 2010 at 17:16, Raymond Hettinger
> <raymond.hettinger at gmail.com> wrote:
>> Of the ideas I've seen in this thread, only two look reasonable:
>> * Do nothing. This is attractive because it doesn't break anything.
>> * Have float.__eq__(x, y) return True whenever x and y are
>> the same NaN object. This is attractive because it is a
>> minimal change that provides a little protection for
>> simple containers.
>> I support either of those options.
> What's the flaw in using isnan()?
There are implicit comparisons being done inside list.__contains__() and other
such methods. They do not, and should not, know about isnan().
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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