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

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Date Fri, 15 Jul 2011 10:18:28 -0700
From Ethan Furman <ethan@stoneleaf.us>
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Subject Re: None versus MISSING sentinel -- request for design feedback
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Mel wrote:
> Steven D'Aprano wrote:
> 
>> Well yes, but None is an explicit missing value too. The question I have
>> is if I should support None as that value, or something else. Or if anyone
>> can put a good case for it, both, or neither and so something completely
>> different.
> 
> If it's any help, I think (some of?) the database interface packages already 
> do just that, returning None when they find NULL fields.

Indeed.  I'm adding Null support to my dbf package now, and while 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) the numeric values 
will be None... although, now that I've seen this thread, I'll add the 
ability to choose what the numeric Null is returned as.

~Ethan~

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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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