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Groups > comp.lang.python > #25431
| From | Dennis Lee Bieber <wlfraed@ix.netcom.com> |
|---|---|
| Subject | Re: Implicit conversion to boolean in if and while statements |
| Date | 2012-07-16 13:28 -0400 |
| Organization | > Bestiaria Support Staff < |
| References | <mailman.2132.1342341291.4697.python-list@python.org> <5002a1f9$0$29995$c3e8da3$5496439d@news.astraweb.com> <mailman.2144.1342371768.4697.python-list@python.org> <50037eab$0$29995$c3e8da3$5496439d@news.astraweb.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.2183.1342459699.4697.python-list@python.org> (permalink) |
On 16 Jul 2012 02:38:35 GMT, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> declaimed the following in
gmane.comp.python.general:
> On Sun, 15 Jul 2012 12:02:37 -0500, Andrew Berg wrote:
>
> > Okay, I see the value in this, but I don't understand why None has a
> > truth value.
>
> And this is exactly the sort of mental confusion that Laura Crichton
> warned about (see the link I included earlier).
>
Would one rather have the behavior seen in SQL for Null?
http://www.firebirdsql.org/file/documentation/reference_manuals/user_manuals/Firebird-Null-Guide.pdf
Hey, let's turn the IF statement into tri-state logic...
if cond:
#true branch
else:
#false branch
unknown:
#when cond includes a None term that was NOT explicitly
#part of a "... is {not} None" clause
--
Wulfraed Dennis Lee Bieber AF6VN
wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/
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Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-15 03:34 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-15 10:56 +0000
Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-15 10:19 -0600
Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2012-07-15 09:50 -0700
Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-15 12:01 -0600
Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2012-07-15 11:56 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 07:53 +1000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 18:21 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 11:51 +1000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 19:31 -0700
Re: Implicit conversion to boolean in if and while statements Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-16 17:57 +0000
Re: Implicit conversion to boolean in if and while statements Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-07-17 00:44 -0400
Re: Implicit conversion to boolean in if and while statements Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-07-15 22:15 -0400
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 19:58 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 04:03 +0000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 21:53 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 15:57 +1000
Re: Implicit conversion to boolean in if and while statements alex23 <wuwei23@gmail.com> - 2012-07-16 00:21 -0700
Re: Implicit conversion to boolean in if and while statements Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-07-17 00:18 -0400
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 06:25 +0000
Re: Implicit conversion to boolean in if and while statements Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-07-17 05:38 -0400
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 02:58 +0000
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 13:05 +1000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 20:21 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 04:20 +0000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 22:03 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 16:00 +1000
Re: Implicit conversion to boolean in if and while statements alex23 <wuwei23@gmail.com> - 2012-07-16 00:27 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 07:52 +0000
Re: Implicit conversion to boolean in if and while statements Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-16 23:26 +0200
Re: Implicit conversion to boolean in if and while statements Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-16 23:17 +0200
Re: Implicit conversion to boolean in if and while statements Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-07-16 07:30 +0100
Re: Implicit conversion to boolean in if and while statements Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-07-16 18:03 +0000
Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2012-07-15 11:56 -0700
Re: Implicit conversion to boolean in if and while statements Serhiy Storchaka <storchaka@gmail.com> - 2012-07-16 16:01 +0300
Re: Implicit conversion to boolean in if and while statements rusi <rustompmody@gmail.com> - 2012-07-16 18:45 -0700
Re: Implicit conversion to boolean in if and while statements Rick Johnson <rantingrickjohnson@gmail.com> - 2012-07-15 09:50 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 02:13 +0000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-15 19:41 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-16 12:58 +1000
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 08:05 +0000
Re: Implicit conversion to boolean in if and while statements Ethan Furman <ethan@stoneleaf.us> - 2012-07-16 11:13 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 06:14 +0000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-15 12:02 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-16 02:38 +0000
Re: Implicit conversion to boolean in if and while statements Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-07-16 13:28 -0400
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 01:12 +0000
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 01:13 +0000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-16 15:33 -0500
Re: Implicit conversion to boolean in if and while statements Ethan Furman <ethan@stoneleaf.us> - 2012-07-16 13:54 -0700
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 00:43 +0000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-16 20:57 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 04:39 +0000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-17 00:19 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 07:08 +0000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-17 03:23 -0500
Re: Implicit conversion to boolean in if and while statements alex23 <wuwei23@gmail.com> - 2012-07-17 18:35 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-17 18:32 +1000
Re: Implicit conversion to boolean in if and while statements Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-17 14:43 +0200
Re: Implicit conversion to boolean in if and while statements Laszlo Nagy <gandalf@shopzeus.com> - 2012-07-17 14:59 +0200
Re: Implicit conversion to boolean in if and while statements Terry Reedy <tjreedy@udel.edu> - 2012-07-17 13:57 -0400
Re: Implicit conversion to boolean in if and while statements Ethan Furman <ethan@stoneleaf.us> - 2012-07-17 05:35 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-17 12:13 +1000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-15 12:16 -0500
Re: Implicit conversion to boolean in if and while statements Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-15 11:45 -0600
Re: Implicit conversion to boolean in if and while statements Terry Reedy <tjreedy@udel.edu> - 2012-07-15 16:09 -0400
Re: Implicit conversion to boolean in if and while statements Terry Reedy <tjreedy@udel.edu> - 2012-07-15 16:28 -0400
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-16 20:22 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 04:11 +0000
Re: Implicit conversion to boolean in if and while statements Ranting Rick <rantingrickjohnson@gmail.com> - 2012-07-16 21:18 -0700
Re: Implicit conversion to boolean in if and while statements Chris Angelico <rosuav@gmail.com> - 2012-07-17 14:24 +1000
Re: Implicit conversion to boolean in if and while statements Andrew Berg <bahamutzero8825@gmail.com> - 2012-07-16 23:44 -0500
Re: Implicit conversion to boolean in if and while statements Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-17 04:47 +0000
Re: Implicit conversion to boolean in if and while statements John Nagle <nagle@animats.com> - 2012-07-17 00:26 -0700
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