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

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Date Fri, 15 Jul 2011 20:38:08 +1000
From Cameron Simpson <cs@zip.com.au>
To Steven D'Aprano <steve+comp.lang.python@pearwood.info>
Subject Re: None versus MISSING sentinel -- request for design feedback
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On 15Jul2011 20:17, Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
| Cameron Simpson wrote:
| > I suppose there's no scope for having the append-to-the-list step sanity
| > check for the sentinel (be it None or otherwise)?
| 
| It is not my responsibility to validate data during construction, only to do
| the right thing when given that data. The right thing being, raise an
| exception if values are not numeric, unless an explicit "missing" value
| (whatever that ends up being).

Well there you go. You need to use MISSING, not None. As you say, None
can easily be a mistake and you want to be sure. If what you describe as
"right" is right, then I too would be using a special sentinal instead
of None.
-- 
Cameron Simpson <cs@zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

The English language has a word to describe a group of anarcho-collectivists
without resorting to spiffy hyphenated coined phrases: a mob.
        - Tim Mefford, <tim@physics.orst.edu>

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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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