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Groups > comp.lang.python > #104689
| From | Mark Lawrence <breamoreboy@yahoo.co.uk> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: Pyhon 2.x or 3.x, which is faster? |
| Date | 2016-03-12 10:51 +0000 |
| Message-ID | <mailman.33.1457779939.12893.python-list@python.org> (permalink) |
| References | (18 earlier) <nbv496$e8q$1@dont-email.me> <mailman.10.1457733601.12893.python-list@python.org> <nbvgds$ed$1@dont-email.me> <MSREy.1473117$wX5.1467333@fx40.am4> <nc0r0q$srq$1@dont-email.me> |
On 12/03/2016 10:31, BartC wrote: > On 12/03/2016 10:06, alister wrote: >> On Fri, 11 Mar 2016 22:24:45 +0000, BartC wrote: >> >>> On 11/03/2016 21:59, Mark Lawrence wrote: >>>> On 11/03/2016 18:57, BartC wrote: >>> >>>> def test(): >>>> s="" >>>> for i in range(10000000): >>>> s+="*" >>>> print (len(s)) >>>> >>>> test() >>> >>>> The minor snag that you might like to correct with your microbenchmark, >>>> which any experienced Python programmer knows, is that you *NEVER, >>>> EVER* >>>> create strings like this. >>> >>> Why not? Chris said his version runs much faster (even allowing for >>> different machines), and might have a special optimisation for it. >>> >>> And I think it can be optimised if, for example, there are no other >>> references to the string that s refers to. >>> >>> So what's wrong with trying to fix it rather that using a workaround? >> >> because the "workarround" is not a workarround it is the correct way to >> do it >> the code above is a workarround for somone who does not know the pythonic >> method to do this >> >> S= "*"*10000000 > > This is a benchmark that measures the cost of adding to a string a > character at a time. > > In practice the final length of the string is not known, and the > characters added at each stage are not known. > > Although the strings won't usually be that big; the benchmark > exaggerates here to highlight a possible issue with += on strings. And > it worked, as there can be big difference with or without the += > optimisation in place. > > It also showed a possible bug or problem with PyPy. > > You can't demonstrate all this by just writing s="*"*10000000. > There is no possible issue with += on strings, there is a known issue. What to do about has all ready been discussed by myself, Dennis Lee Bieber, Michael Torrie and Steven D'Aprano, but you've chosen to ignore what we've written. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence
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Pyhon 2.x or 3.x, which is faster? Tony van der Hoff <tony@vanderhoff.org> - 2016-03-06 11:34 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-07 01:41 +1100
Re: Pyhon 2.x or 3.x, which is faster? Tony van der Hoff <tony@vanderhoff.org> - 2016-03-07 10:45 +0000
Re: Pyhon 2.x or 3.x, which is faster? Andrew Jaffe <a.h.jaffe@gmail.com> - 2016-03-07 11:54 +0000
Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 17:33 -0500
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 11:02 +0000
Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-07 13:11 +0200
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 11:38 +0000
Re: Pyhon 2.x or 3.x, which is faster? Fabien <fabien.maussion@gmail.com> - 2016-03-07 13:19 +0100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 13:25 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 02:31 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 18:34 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 06:10 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 20:19 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 07:47 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 22:39 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 10:40 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 00:22 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 00:43 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 11:45 +1100
Re: Pyhon 2.x or 3.x, which is faster? MRAB <python@mrabarnett.plus.com> - 2016-03-08 00:47 +0000
Re: Pyhon 2.x or 3.x, which is faster? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-03-07 20:29 -0500
Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 22:51 -0500
Re: Pyhon 2.x or 3.x, which is faster? Michael Torrie <torriem@gmail.com> - 2016-03-08 17:34 -0700
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 13:01 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-09 11:38 +1100
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 11:05 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:00 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 01:12 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:47 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 02:45 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:09 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 16:09 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 19:15 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 20:44 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 22:38 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 10:59 +1100
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 08:40 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 12:02 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 21:13 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 23:14 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 23:35 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 00:58 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 12:28 +1100
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 07:30 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 11:50 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 12:15 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 12:47 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 00:08 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 14:22 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 19:26 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-11 16:29 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-11 18:57 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-11 21:59 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-11 22:24 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-12 16:59 +1100
Re: Pyhon 2.x or 3.x, which is faster? alister <alister.ware@ntlworld.com> - 2016-03-12 10:06 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-12 10:31 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-12 10:51 +0000
Re: Pyhon 2.x or 3.x, which is faster? alister <alister.ware@ntlworld.com> - 2016-03-12 15:36 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-13 14:22 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-12 10:34 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-12 21:40 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 07:07 +1100
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-11 16:06 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 16:36 +1100
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 13:18 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 00:30 +1100
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 13:46 +0000
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 18:43 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 18:55 +1100
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 12:59 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 12:19 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 10:38 +1100
Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 23:48 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 11:03 +1100
Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-10 02:38 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 14:43 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 01:30 +0000
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 13:29 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 14:32 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 13:45 +1100
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 11:21 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:23 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:33 +0000
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 12:38 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:40 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 02:02 +0000
Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 13:28 +1100
Re: Pyhon 2.x or 3.x, which is faster? MRAB <python@mrabarnett.plus.com> - 2016-03-08 02:47 +0000
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:15 +0000
Re: Pyhon 2.x or 3.x, which is faster? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-08 13:45 +0200
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 12:09 +0000
Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 22:39 -0500
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 03:48 +0000
What will I get when reading from a file? (was: Pyhon 2.x or 3.x, which is faster?) Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 11:09 +1100
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 13:12 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:53 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 10:28 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 00:09 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-09 11:36 +1100
Re: Pyhon 2.x or 3.x, which is faster? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-03-08 21:03 -0500
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 03:07 +1100
Re: Pyhon 2.x or 3.x, which is faster? Serhiy Storchaka <storchaka@gmail.com> - 2016-03-08 14:48 +0200
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 12:34 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:49 +1100
Re: Pyhon 2.x or 3.x, which is faster? Serhiy Storchaka <storchaka@gmail.com> - 2016-03-08 15:05 +0200
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 12:19 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:41 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-08 15:40 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 13:49 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 16:15 +0000
Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-08 09:23 -0800
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 19:02 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 11:04 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 01:28 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 13:18 +1100
Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-09 02:11 -0800
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 14:03 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 01:11 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 14:39 +0000
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 01:54 +1100
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:33 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 02:58 +1100
Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 14:56 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:28 +1100
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 01:57 +1100
Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 02:04 +1100
Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 16:53 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 01:54 +1100
Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 15:06 +0000
Re: Pyhon 2.x or 3.x, which is faster? Tim Golden <mail@timgolden.me.uk> - 2016-03-09 15:15 +0000
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:38 +1100
Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-09 10:42 -0500
Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-09 09:04 -0800
Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-09 08:08 +0200
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 22:52 +1100
Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-09 14:53 +0200
Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 03:53 +1100
Re: Pyhon 2.x or 3.x, which is faster? Michael Torrie <torriem@gmail.com> - 2016-03-08 17:42 -0700
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 02:53 +0000
Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-07 19:02 +0000
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