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Groups > comp.lang.python > #79600
| References | (6 earlier) <M452w.582708$Ym.533586@fx05.am4> <878uk6x5nd.fsf@elektro.pacujo.net> <544a1016$0$13000$c3e8da3$5496439d@news.astraweb.com> <87tx2tvmea.fsf@elektro.pacujo.net> <544a4ef7$0$12984$c3e8da3$5496439d@news.astraweb.com> |
|---|---|
| From | Ian Kelly <ian.g.kelly@gmail.com> |
| Date | 2014-10-24 12:22 -0600 |
| Subject | Re: (test) ? a:b |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.15143.1414174996.18130.python-list@python.org> (permalink) |
On Fri, Oct 24, 2014 at 7:07 AM, Steven D'Aprano <steve+comp.lang.python@pearwood.info> >> if j < 10: >> j += 1 >> else: >> j = 3 >> >> or: >> >> j = j + 1 if j < 10 else 3 >> >> or: >> >> j = (lambda: 3, lambda: j + 1)[j < 10]() > > Certainly not the third one. That's needlessly obfuscated for the sake of > premature optimization. This version is much better, and probably not only > simpler and easier to read but probably more efficient too: > > j = (3, j + 1)[j < 10] Yes, the lambda approach falls victim to function calls being slow. $ python3 -m timeit -s "j = 5" "if j < 10: j+=1 > else: j=3" 10000000 loops, best of 3: 0.0513 usec per loop $ python3 -m timeit -s "j = 5" "j = j + 1 if j < 10 else 3" 10000000 loops, best of 3: 0.0519 usec per loop $ python3 -m timeit -s "j = 5" "j = (3, j+1)[j < 10]" 10000000 loops, best of 3: 0.0883 usec per loop $ python3 -m timeit -s "j = 5" "j = (lambda: 3, lambda: j+1)[j < 10]()" 1000000 loops, best of 3: 0.312 usec per loop
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(test) ? a:b "ast" <nomail@invalid.com> - 2014-10-22 10:29 +0200
Re: (test) ? a:b buscacio@gmail.com - 2014-10-22 02:05 -0700
Re: (test) ? a:b "ast" <nomail@invalid.com> - 2014-10-22 11:14 +0200
Re: (test) ? a:b Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-10-22 12:45 +0100
Re: (test) ? a:b "ast" <nomail@invalid.com> - 2014-10-27 09:01 +0100
Re: (test) ? a:b Michael Torrie <torriem@gmail.com> - 2014-10-22 11:16 -0600
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-23 11:44 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-22 20:15 +1100
Re: (test) ? a:b Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-10-22 10:16 +0100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-22 20:27 +1100
Re: (test) ? a:b Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-10-23 16:46 +1300
Re: (test) ? a:b MRAB <python@mrabarnett.plus.com> - 2014-10-23 11:12 +0100
Re: (test) ? a:b "ast" <nomail@invalid.com> - 2014-10-24 08:38 +0200
Re: (test) ? a:b Michael Torrie <torriem@gmail.com> - 2014-10-25 19:04 -0600
Re: (test) ? a:b Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-10-27 22:04 +1300
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-26 12:20 +1100
Re: (test) ? a:b Michael Torrie <torriem@gmail.com> - 2014-10-25 21:05 -0600
Re: (test) ? a:b Ned Batchelder <ned@nedbatchelder.com> - 2014-10-22 07:30 -0400
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-22 14:41 +0300
Re: (test) ? a:b Rustom Mody <rustompmody@gmail.com> - 2014-10-22 06:16 -0700
Re: (test) ? a:b "BartC" <bc@freeuk.com> - 2014-10-22 19:08 +0100
Re: (test) ? a:b Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-10-22 19:55 -0400
Re: (test) ? a:b "BartC" <bc@freeuk.com> - 2014-10-23 11:50 +0100
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-23 16:44 +0300
Re: (test) ? a:b Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-23 08:24 -0600
Re: (test) ? a:b Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-10-23 16:41 +0200
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-23 19:20 +0300
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-24 19:38 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-24 19:45 +1100
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-24 12:37 +0300
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-25 00:07 +1100
Re: (test) ? a:b Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-24 12:22 -0600
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-24 21:46 +0300
Re: (test) ? a:b Dan Stromberg <drsalists@gmail.com> - 2014-10-24 10:20 -0700
Re: (test) ? a:b alister <alister.nospam.ware@ntlworld.com> - 2014-10-24 20:58 +0000
Re: (test) ? a:b Marko Rauhamaa <marko@pacujo.net> - 2014-10-25 00:02 +0300
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-25 16:03 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-25 16:25 +1100
Re: (test) ? a:b Ned Batchelder <ned@nedbatchelder.com> - 2014-10-25 07:58 -0400
Re: (test) ? a:b Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-25 07:53 -0600
Re: (test) ? a:b Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-10-25 14:11 -0400
Re: (test) ? a:b alister <alister.nospam.ware@ntlworld.com> - 2014-10-25 19:49 +0000
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-26 07:45 +1100
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-26 11:10 +1100
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-26 12:03 +1100
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-26 15:15 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-26 15:34 +1100
Re: (test) ? a:b Terry Reedy <tjreedy@udel.edu> - 2014-10-26 17:12 -0400
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-27 11:38 +1100
Re: (test) ? a:b MRAB <python@mrabarnett.plus.com> - 2014-10-27 01:40 +0000
Re: (test) ? a:b Rustom Mody <rustompmody@gmail.com> - 2014-10-26 19:19 -0700
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-26 12:10 +1100
Re: (test) ? a:b Joshua Landau <joshua@landau.ws> - 2014-10-27 01:55 +0000
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-27 13:28 +1100
Re: (test) ? a:b Rustom Mody <rustompmody@gmail.com> - 2014-10-26 19:38 -0700
Re: (test) ? a:b Joshua Landau <joshua@landau.ws> - 2014-10-27 02:43 +0000
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-27 13:56 +1100
Re: (test) ? a:b Dan Stromberg <drsalists@gmail.com> - 2014-10-25 15:34 -0700
Re: (test) ? a:b Ben Finney <ben+python@benfinney.id.au> - 2014-10-26 10:53 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-26 11:01 +1100
Re: (test) ? a:b Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-10-26 01:09 +0100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-26 11:13 +1100
Re: (test) ? a:b Vito De Tullio <vito.detullio@gmail.com> - 2014-10-23 06:55 +0200
Re: (test) ? a:b Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-23 03:28 +1100
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-23 03:40 +1100
Re: (test) ? a:b alister <alister.nospam.ware@ntlworld.com> - 2014-10-22 18:03 +0000
Re: (test) ? a:b Matthew Ruffalo <mmr15@case.edu> - 2014-10-22 14:27 -0400
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-23 05:30 +1100
Re: (test) ? a:b Ned Batchelder <ned@nedbatchelder.com> - 2014-10-22 16:11 -0400
Re: (test) ? a:b Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-10-22 12:41 +0100
Re: (test) ? a:b alister <alister.nospam.ware@ntlworld.com> - 2014-10-22 15:12 +0000
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-23 02:18 +1100
Re: (test) ? a:b alister <alister.nospam.ware@ntlworld.com> - 2014-10-22 15:24 +0000
Re: (test) ? a:b Dan Stromberg <drsalists@gmail.com> - 2014-10-22 09:09 -0700
Re: (test) ? a:b Tobiah <toby@tobiah.org> - 2014-10-24 10:23 -0700
Re: (test) ? a:b Chris Angelico <rosuav@gmail.com> - 2014-10-25 04:27 +1100
Re: (test) ? a:b Tobiah <toby@tobiah.org> - 2014-10-24 11:31 -0700
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