Proposal: === and !=== operators
Steven D'Aprano
steve+comp.lang.python at pearwood.info
Wed Jul 9 21:10:24 EDT 2014
On Wed, 09 Jul 2014 13:05:22 -0500, Tim Chase wrote:
> If you want to compare things in a NaN-aware way, you can either spell
> it out explicitly:
>
> if x == y or (math.isnan(x) and math.isnan(y)):
> do_stuff()
But do we really want any arbitrary NAN to compare equal-ish with every
other NAN? There are 9007199254740990 distinct NANs (slightly less than
0.05% of the total number of floats).
Much to my disappointment, frexp doesn't return the payload and exponent
of NANs, at least not on Linux:
py> math.frexp(NAN)
(nan, 0)
so it can't be used to distinguish different NANs.
--
Steven
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