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Groups > comp.lang.python > #9591

Re: None versus MISSING sentinel -- request for design feedback

From Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups comp.lang.python
Subject Re: None versus MISSING sentinel -- request for design feedback
Date 2011-07-16 14:24 +1200
Message-ID <98cb2oF3vpU1@mid.individual.net> (permalink)
References (2 earlier) <4e201a9d$0$29989$c3e8da3$5496439d@news.astraweb.com> <mailman.1060.1310727853.1164.python-list@python.org> <4e203706$0$29972$c3e8da3$5496439d@news.astraweb.com> <ivpeip$l9$1@speranza.aioe.org> <mailman.1071.1310749444.1164.python-list@python.org>

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Ethan Furman wrote:
> some 
> of the return values (Logical, Date, DateTime, and probably Character) 
> will have their own dedicated singletons (Null, NullDate, NullDateTime, 
> NullChar -- which will all compare equal to None)

That doesn't seem like a good idea to me. It's common practice
to use 'is' rather than '==' when comparing things to None.

Why do you want to use special null values for these types?

-- 
Greg

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Thread

None versus MISSING sentinel -- request for design feedback Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-15 15:28 +1000
  Re: None versus MISSING sentinel -- request for design feedback Chris Angelico <rosuav@gmail.com> - 2011-07-15 16:08 +1000
    Re: None versus MISSING sentinel -- request for design feedback "bruno.desthuilliers@gmail.com" <bruno.desthuilliers@gmail.com> - 2011-07-15 00:53 -0700
    Re: None versus MISSING sentinel -- request for design feedback Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-15 20:46 +1000
      Re: None versus MISSING sentinel -- request for design feedback Chris Angelico <rosuav@gmail.com> - 2011-07-15 21:04 +1000
        Re: None versus MISSING sentinel -- request for design feedback Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-15 22:48 +1000
          Re: None versus MISSING sentinel -- request for design feedback Mel <mwilson@the-wire.com> - 2011-07-15 09:16 -0400
            Re: None versus MISSING sentinel -- request for design feedback Ethan Furman <ethan@stoneleaf.us> - 2011-07-15 10:18 -0700
              Re: None versus MISSING sentinel -- request for design feedback Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2011-07-16 14:24 +1200
                Re: None versus MISSING sentinel -- request for design feedback Ethan Furman <ethan@stoneleaf.us> - 2011-07-16 17:31 -0700
  Re: None versus MISSING sentinel -- request for design feedback Rob Williscroft <rtw@rtw.me.uk> - 2011-07-15 07:43 +0000
    Re: None versus MISSING sentinel -- request for design feedback Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-15 20:19 +1000
      Re: None versus MISSING sentinel -- request for design feedback "OKB (not okblacke)" <brenNOSPAMbarn@NObrenSPAMbarn.net> - 2011-07-15 17:40 +0000
      Re: None versus MISSING sentinel -- request for design feedback Terry Reedy <tjreedy@udel.edu> - 2011-07-15 17:35 -0400
  Re: None versus MISSING sentinel -- request for design feedback Cameron Simpson <cs@zip.com.au> - 2011-07-15 17:44 +1000
    Re: None versus MISSING sentinel -- request for design feedback "bruno.desthuilliers@gmail.com" <bruno.desthuilliers@gmail.com> - 2011-07-15 02:58 -0700
    Re: None versus MISSING sentinel -- request for design feedback Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-07-15 20:17 +1000
      Re: None versus MISSING sentinel -- request for design feedback Cameron Simpson <cs@zip.com.au> - 2011-07-15 20:38 +1000
  Re: None versus MISSING sentinel -- request for design feedback "bruno.desthuilliers@gmail.com" <bruno.desthuilliers@gmail.com> - 2011-07-15 00:59 -0700
  Re: None versus MISSING sentinel -- request for design feedback Teemu Likonen <tlikonen@iki.fi> - 2011-07-15 11:28 +0300
    Re: None versus MISSING sentinel -- request for design feedback "bruno.desthuilliers@gmail.com" <bruno.desthuilliers@gmail.com> - 2011-07-15 03:02 -0700
      Re: None versus MISSING sentinel -- request for design feedback Teemu Likonen <tlikonen@iki.fi> - 2011-07-15 13:56 +0300
  Re: None versus MISSING sentinel -- request for design feedback Eric Snow <ericsnowcurrently@gmail.com> - 2011-07-15 11:02 -0600

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