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| To | python-list@python.org |
| From | Ben Finney <ben+python@benfinney.id.au> |
| Subject | Re: Reference |
| Date | Tue, 04 Mar 2014 09:17:55 +1100 |
| References | <53144e8d$0$2149$426a74cc@news.free.fr> <1d1dfa1b-b715-4d8f-9c12-f0d3dc1a22c9@googlegroups.com> <85ppm3httu.fsf@benfinney.id.au> <lf2sjk$7d4$1@ger.gmane.org> <20140303155112.46e34ff8@bigbox.christie.dr> <CADwdpyYP1XzcSRq38g4ugED8HEaZN3KOFmQMwXcojnLqQSiwgw@mail.gmail.com> |
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Jerry Hill <malaclypse2@gmail.com> writes: > if foo == None: > do_stuff() > > The only time it would give you a different result from the "is" > version is if foo was bound to an object that returned True when > compared with None. That's right. Python provides this singleton and then recommends you compare with ‘is’, precisely to protect against pathological cases like a “return True when compared for equality with None” data type. Using ‘if foo is None’ means you don't even have to spend time worrying about such cases. > And if that were the case, I'm still not convinced that you can tell > from looking at those two lines of code which one is buggy, except for > the fact that there has been 20 years of custom saying that comparing > to None with equality is wrong. Yes. And because of that widespread convention, it's much more correct to compare against None with ‘is’. -- \ “Always do right. This will gratify some people, and astonish | `\ the rest.” —Mark Twain | _o__) | Ben Finney
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Reference "ast" <nomail@invalid.com> - 2014-03-03 10:42 +0100
Object identity (was: Reference) Ben Finney <ben+python@benfinney.id.au> - 2014-03-03 21:00 +1100
Re: Object identity (was: Reference) "ast" <nomail@invalid.com> - 2014-03-03 11:21 +0100
Re: Reference "Mark H. Harris" <harrismh777@gmail.com> - 2014-03-03 05:09 -0800
Re: Reference Grant Edwards <invalid@invalid.invalid> - 2014-03-03 14:29 +0000
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-03 07:52 -0800
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 08:10 +1100
Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-03 15:24 -0600
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 08:31 +1100
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-03 21:35 +0000
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-04 00:07 +0200
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:18 +1100
Re: Reference Alister <alister.ware@ntlworld.com> - 2014-03-04 11:10 +0000
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-04 11:48 +0000
Re: Reference "Rhodri James" <rhodri@wildebst.org.uk> - 2014-03-05 00:25 +0000
Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-03 15:51 -0600
Re: Reference Jerry Hill <malaclypse2@gmail.com> - 2014-03-03 17:02 -0500
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-04 00:22 +0200
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 09:27 +1100
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:33 +1100
Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 04:52 +0000
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 16:24 +1100
Re: Reference "Rhodri James" <rhodri@wildebst.org.uk> - 2014-03-05 01:08 +0000
Re: Reference Roy Smith <roy@panix.com> - 2014-03-04 21:09 -0500
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 19:36 -0800
Re: Reference Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-04 21:08 -0700
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 20:31 -0800
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 15:32 +1100
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 20:47 -0800
Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-05 05:06 +0000
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 21:47 -0800
Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-05 16:01 +1000
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:10 -0800
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:22 +1100
Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-05 16:28 +1000
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:24 +0000
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:21 +0000
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:20 +1100
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-05 09:40 -0800
Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 12:12 -0600
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 05:33 +1100
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-05 18:19 +0000
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:23 +0200
Re: Reference Grant Edwards <invalid@invalid.invalid> - 2014-03-05 20:31 +0000
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:46 +0200
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:07 +1100
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:10 +1100
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 21:34 +0000
Re: Reference Terry Reedy <tjreedy@udel.edu> - 2014-03-05 18:00 -0500
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-06 03:01 +0000
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:03 -0800
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:26 +1100
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 17:32 +1100
Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 08:24 -0600
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-05 18:29 +0000
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:34 +0200
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:01 +1100
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 23:14 +0200
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-06 08:26 +1100
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 23:50 +0200
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-06 00:35 +0000
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-06 11:50 +1100
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-06 17:46 +0000
Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 15:33 -0600
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:37 +1100
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-06 02:52 +0200
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 12:05 +1100
Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-06 12:12 +1000
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 21:46 +0000
Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 08:23 +0200
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:33 -0800
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:40 +1100
Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:35 +0000
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 23:45 +1100
Re: Reference Jerry Hill <malaclypse2@gmail.com> - 2014-03-04 10:19 -0500
Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-04 15:42 +0000
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 03:02 +1100
Re: Reference Roy Smith <roy@panix.com> - 2014-03-04 11:14 -0500
Re: Reference MRAB <python@mrabarnett.plus.com> - 2014-03-04 17:12 +0000
Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 08:24 -0800
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 02:25 +1100
Re: Reference Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2014-03-05 14:37 +0100
Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 03:59 +0000
Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:17 +1100
Re: Reference Roy Smith <roy@panix.com> - 2014-03-03 18:02 -0500
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 10:09 +1100
Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 04:38 +0000
Re: Reference Terry Reedy <tjreedy@udel.edu> - 2014-03-03 13:48 -0500
Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 03:45 +0000
Re: Reference Alexander Blinne <news@blinne.net> - 2014-03-04 13:55 +0100
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 01:06 +1100
Re: Reference Alexander Blinne <news@blinne.net> - 2014-03-04 22:53 +0100
Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 09:01 +1100
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