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Re: checking if two things do not equal None

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On 2014-03-29 18:41, Roy Smith wrote:
> On Mar 29, 2014, at 6:36 PM, Tim Chase wrote:
> 
> > And for cases where you have more than one or two things to test
> > for None-itude, you could use
> > 
> >  if all(x is None for x in [a, b, c, d]):
> >    do_something_if_theyre_all_None()
> 
> I might have written that as:
> 
> if set([a, b, c, d]) == set(None)
> 
> That's even clearer if you happen to already have the items in an
> iterable:
> 
> if set(conditions) == set(None)

Though am I correct that your iteration tests for equality, while
mine tests for identity?  Also, my version bails early in the event
quitting early is possible.  That's particularly useful in the case
of doing something like

  if all(x() is None for x in [func1, func2, func3, costly_func]):
    do_something()

-tkc

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checking if two things do not equal None contact.trigon@gmail.com - 2014-03-29 11:56 -0700
  Re: checking if two things do not equal None Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-29 19:05 +0000
    Re: checking if two things do not equal None contact.trigon@gmail.com - 2014-03-29 12:23 -0700
    Re: checking if two things do not equal None Lele Gaifax <lele@metapensiero.it> - 2014-03-29 20:24 +0100
    Re: checking if two things do not equal None Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-29 22:01 +0100
      Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-29 17:07 -0400
        Re: checking if two things do not equal None Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-29 22:55 +0100
          Re: checking if two things do not equal None Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-03-29 23:02 +0100
        Re: checking if two things do not equal None Dave Angel <davea@davea.name> - 2014-03-29 18:01 -0400
          Re: checking if two things do not equal None contact.trigon@gmail.com - 2014-03-29 16:20 -0700
        Re: checking if two things do not equal None Tim Chase <python.list@tim.thechases.com> - 2014-03-29 17:36 -0500
          Re: checking if two things do not equal None Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-30 02:24 +0000
            Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-29 22:43 -0400
              Re: checking if two things do not equal None Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-03-29 22:04 -0500
        Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-29 18:41 -0400
        Re: checking if two things do not equal None Tim Chase <tim@thechases.com> - 2014-03-29 17:46 -0500
          Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-29 18:51 -0400
        Re: checking if two things do not equal None Chris Angelico <rosuav@gmail.com> - 2014-03-30 10:17 +1100
        Re: checking if two things do not equal None Tim Chase <python.list@tim.thechases.com> - 2014-03-29 20:19 -0500
        Re: checking if two things do not equal None Chris Angelico <rosuav@gmail.com> - 2014-03-30 12:37 +1100
        Re: checking if two things do not equal None Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-30 02:04 +0000
          Re: checking if two things do not equal None Chris Angelico <rosuav@gmail.com> - 2014-03-30 13:15 +1100
            Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-29 22:39 -0400
              Re: checking if two things do not equal None Rustom Mody <rustompmody@gmail.com> - 2014-03-29 19:54 -0700
                Re: checking if two things do not equal None Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-30 06:08 +0000
                Re: checking if two things do not equal None Roy Smith <roy@panix.com> - 2014-03-30 08:21 -0400
                Re: checking if two things do not equal None MRAB <python@mrabarnett.plus.com> - 2014-03-30 14:58 +0100
                Re: checking if two things do not equal None Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-03-31 11:48 +1300
              Re: checking if two things do not equal None Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-03-30 19:41 +1300
                Re: checking if two things do not equal None Marko Rauhamaa <marko@pacujo.net> - 2014-03-30 10:37 +0300
            Re: checking if two things do not equal None Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-30 05:54 +0000
              Re: checking if two things do not equal None Chris Angelico <rosuav@gmail.com> - 2014-03-30 17:17 +1100
              Re: checking if two things do not equal None Ben Finney <ben+python@benfinney.id.au> - 2014-03-30 17:52 +1100
              Re: checking if two things do not equal None Chris Angelico <rosuav@gmail.com> - 2014-03-30 18:36 +1100
      Re: checking if two things do not equal None Ethan Furman <ethan@stoneleaf.us> - 2014-03-29 16:20 -0700
  Re: checking if two things do not equal None Terry Reedy <tjreedy@udel.edu> - 2014-03-29 19:02 -0400
  Re: checking if two things do not equal None Jeremy Sanders <jeremy@jeremysanders.net> - 2014-03-31 09:56 +0200
    Re: checking if two things do not equal None Abe <contact.trigon@gmail.com> - 2014-03-31 10:28 -0700
      Re: checking if two things do not equal None Moritz Emanuel Beber <moritz.beber@gmail.com> - 2014-03-31 21:22 +0200

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