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Date: Wed, 9 Jul 2014 13:05:22 -0500
From: Tim Chase <python.list@tim.thechases.com>
To: Steven D'Aprano <steve+comp.lang.python@pearwood.info>
Subject: Re: Proposal: === and !=== operators
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Xref: csiph.com comp.lang.python:74269

On 2014-07-09 12:48, Steven D'Aprano wrote:
> On Wed, 09 Jul 2014 08:27:28 -0400, Roy Smith wrote:
> 
> > We would have *three* ways to compare for equality (==, ===, and
> > is).
> 
> `is` does not, never has, and never will, be a test for equality.
> 
> py> x = []
> py> y = []
> py> x is y
> False

I too am in the -1 category for adding an extra operator-suite
because of the confusion it will add (this is one of my biggest
pet peeves with PHP/JS).

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()

or create a wrapper function to do that for you:

 def equalish(x, y):
   return x == y or (math.isnan(x) and math.isnan(y))

 if equalish(w, z):
   print("yep")
 else:
   print("nope")

-tkc