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Groups > comp.lang.python > #74262

Re: NaN comparisons - Call For Anecdotes

Date 2014-07-09 18:24 +0200
From "Anders J. Munch" <2014@jmunch.dk>
Organization .
Subject Re: NaN comparisons - Call For Anecdotes
References (1 earlier) <53bc26ca$0$29995$c3e8da3$5496439d@news.astraweb.com> <mailman.11653.1404846131.18130.python-list@python.org> <53bc8861$0$29995$c3e8da3$5496439d@news.astraweb.com> <53BD5ADF.2050409@jmunch.dk> <CAPTjJmr_d2f2CbFNOk4Osp9jhz=FskBi-LtDvAftGX2zrgLW1w@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.11697.1404923089.18130.python-list@python.org> (permalink)

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Chris Angelico:
> If you need to do bitwise comparisons, then the easiest way is to use
> the bitpattern, converted to an integer. A 64-bit float becomes a
> 64-bit integer. It's then very simple to compare them, and reflexivity
> is maintained. At what point do you actually need them to be floats?
> What are you really doing with them?

What does one do with floats? Add, subtract, multipy, divide, display, input, 
store and retrieve to and from various formats.
All the usual stuff. Why would my use be different from anyone elses?

What you and Steven seem to be saying is that I should employ strategies to 
avoid NaNs ever being compared. I'll take that one step further and say that as 
long as NaN!=NaN, everyone should seek to avoid NaNs ever being compared.

regards, Anders

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Thread

NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-08 16:53 +0200
  Re: NaN comparisons - Call For Anecdotes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-07-08 17:13 +0000
    Re: NaN comparisons - Call For Anecdotes Chris Angelico <rosuav@gmail.com> - 2014-07-09 03:21 +1000
    Re: NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-08 21:02 +0200
      Re: NaN comparisons - Call For Anecdotes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-07-09 00:10 +0000
        Re: NaN comparisons - Call For Anecdotes Terry Reedy <tjreedy@udel.edu> - 2014-07-09 00:57 -0400
          Re: NaN comparisons - Call For Anecdotes Steven D'Aprano <steve@pearwood.info> - 2014-07-09 06:43 +0000
            Re: NaN comparisons - Call For Anecdotes Chris Angelico <rosuav@gmail.com> - 2014-07-09 16:52 +1000
        Re: NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-09 17:08 +0200
          Re: NaN comparisons - Call For Anecdotes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-07-09 16:53 +0000
            Re: NaN comparisons - Call For Anecdotes Ian Kelly <ian.g.kelly@gmail.com> - 2014-07-09 11:26 -0600
            Re: NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-09 19:44 +0200
        Re: NaN comparisons - Call For Anecdotes Chris Angelico <rosuav@gmail.com> - 2014-07-10 01:13 +1000
        Re: NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-09 18:24 +0200
    Re: NaN comparisons - Call For Anecdotes "Anders J. Munch" <2014@jmunch.dk> - 2014-07-08 21:25 +0200
  Re: NaN comparisons - Call For Anecdotes Rustom Mody <rustompmody@gmail.com> - 2014-07-09 20:07 -0700

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