float("nan") in set or as key

Robert Kern robert.kern at gmail.com
Thu Jun 2 13:04:00 EDT 2011


On 6/2/11 8:05 AM, Grant Edwards wrote:

> Two of my perennial complaints about Python's handling of NaNs and
> Infs:
>
>   1) They weren't handle by pickle et al.
>
>   2) The string representations produced by repr() and accepted by
>      float() weren't standardized across platforms.
>
> I think the latter has finally been fixed, hasn't it?

And the former!

Python 2.7.1 |EPD 7.0-2 (32-bit)| (r271:86832, Dec  3 2010, 15:41:32)
[GCC 4.0.1 (Apple Inc. build 5488)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> inf = 1e300*1e300
 >>> nan = inf / inf
 >>> import cPickle
 >>> cPickle.loads(cPickle.dumps(nan))
nan
 >>> cPickle.loads(cPickle.dumps(inf))
inf

-- 
Robert Kern

"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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