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Groups > comp.lang.python > #66218
| From | Peter Otten <__peter__@web.de> |
|---|---|
| Subject | Re: A curious bit of code... |
| Date | 2014-02-13 20:43 +0100 |
| Organization | None |
| References | <4cc09129-43ee-4205-a24c-03f92b594abc@googlegroups.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.6864.1392320644.18130.python-list@python.org> (permalink) |
forman.simon@gmail.com wrote:
> I ran across this and I thought there must be a better way of doing it,
> but then after further consideration I wasn't so sure.
>
> if key[:1] + key[-1:] == '<>': ...
>
>
> Some possibilities that occurred to me:
>
> if key.startswith('<') and key.endswith('>'): ...
>
> and:
>
> if (key[:1], key[-1:]) == ('<', '>'): ...
>
>
> I haven't run these through a profiler yet, but it seems like the original
> might be the fastest after all?
$ python -m timeit -s 's = "<alpha>"' 's[:1]+s[-1:] == "<>"'
1000000 loops, best of 3: 0.37 usec per loop
$ python -m timeit -s 's = "<alpha>"' 's[:1] == "<" and s[-1:] == ">"'
1000000 loops, best of 3: 0.329 usec per loop
$ python -m timeit -s 's = "<alpha>"' 's.startswith("<") and
s.endswith(">")'
1000000 loops, best of 3: 0.713 usec per loop
The first is too clever for my taste.
The second is fast and easy to understand. It might attract "improvements"
replacing the slice with an index, but I trust you will catch that with your
unit tests ;)
Personally, I'm willing to spend the few extra milliseconds and use the
foolproof third.
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A curious bit of code... forman.simon@gmail.com - 2014-02-13 10:37 -0800
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-13 13:45 -0500
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 10:45 -0800
Re: A curious bit of code... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-02-13 19:09 +0000
Re: A curious bit of code... Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-02-13 20:05 +0100
Re: A curious bit of code... Neil Cerutti <neilc@norwich.edu> - 2014-02-13 19:17 +0000
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 11:20 -0800
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-13 14:28 -0500
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 11:25 -0800
Re: A curious bit of code... Neil Cerutti <neilc@norwich.edu> - 2014-02-13 19:25 +0000
Re: A curious bit of code... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-02-13 19:32 +0000
Re: A curious bit of code... Peter Otten <__peter__@web.de> - 2014-02-13 20:43 +0100
Re: A curious bit of code... Marko Rauhamaa <marko@pacujo.net> - 2014-02-13 21:56 +0200
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 11:23 -0800
Re: A curious bit of code... Neil Cerutti <neilc@norwich.edu> - 2014-02-13 19:51 +0000
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 11:59 -0800
Re: A curious bit of code... Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-13 13:59 -0600
Re: A curious bit of code... Chris Angelico <rosuav@gmail.com> - 2014-02-14 07:29 +1100
Re: A curious bit of code... Tim Chase <python.list@tim.thechases.com> - 2014-02-13 14:39 -0600
Re: A curious bit of code... Emile van Sebille <emile@fenx.com> - 2014-02-13 12:55 -0800
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-13 16:24 -0500
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 16:23 -0800
Re: A curious bit of code... Chris Angelico <rosuav@gmail.com> - 2014-02-14 08:01 +1100
Re: A curious bit of code... Neil Cerutti <neilc@norwich.edu> - 2014-02-13 21:01 +0000
Re: A curious bit of code... Peter Otten <__peter__@web.de> - 2014-02-13 22:06 +0100
Re: A curious bit of code... Chris Angelico <rosuav@gmail.com> - 2014-02-14 08:10 +1100
Re: A curious bit of code... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-02-13 21:14 +0000
Re: A curious bit of code... Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-13 15:20 -0600
Re: A curious bit of code... Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-13 15:19 -0600
Re: A curious bit of code... Emile van Sebille <emile@fenx.com> - 2014-02-13 13:23 -0800
Re: A curious bit of code... Chris Angelico <rosuav@gmail.com> - 2014-02-14 08:31 +1100
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-13 16:38 -0500
Re: A curious bit of code... Zachary Ware <zachary.ware+pylist@gmail.com> - 2014-02-13 15:47 -0600
Re: A curious bit of code... Serhiy Storchaka <storchaka@gmail.com> - 2014-02-13 23:49 +0200
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-13 16:51 -0500
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 13:33 -0800
Re: A curious bit of code... Chris Angelico <rosuav@gmail.com> - 2014-02-14 09:13 +1100
Re: A curious bit of code... Ethan Furman <ethan@stoneleaf.us> - 2014-02-13 14:26 -0800
Re: A curious bit of code... Terry Reedy <tjreedy@udel.edu> - 2014-02-13 19:29 -0500
Re: A curious bit of code... forman.simon@gmail.com - 2014-02-13 18:45 -0800
Re: A curious bit of code... Ned Batchelder <ned@nedbatchelder.com> - 2014-02-13 22:26 -0500
Re: A curious bit of code... forman.simon@gmail.com - 2014-02-14 12:04 -0800
Re: A curious bit of code... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-02-14 21:01 +0000
Re: A curious bit of code... Dave Angel <davea@davea.name> - 2014-02-14 07:19 -0500
Re: A curious bit of code... Roy Smith <roy@panix.com> - 2014-02-14 09:06 -0500
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