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Re: A curious bit of code...

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Date Fri, 14 Feb 2014 09:13:28 +1100
Subject Re: A curious bit of code...
From Chris Angelico <rosuav@gmail.com>
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On Fri, Feb 14, 2014 at 8:33 AM, Ethan Furman <ethan@stoneleaf.us> wrote:
> Oh, it's not that bad!  All you have to do is handle the edge case of an
> empty string:
>
> s[::len(s)-1 if s else True]
>
> *ducks and runs*

And the edge case of the one-character string. Also, it's been noted
that calling the built-in function len() is slow, so I propose
changing that.

s[::(sys.getsizeof("\N{MATHEMATICAL BOLD CAPITAL
L}"+s)-sys.getsizeof("\N{MATHEMATICAL BOLD CAPITAL E}\N{MATHEMATICAL
BOLD CAPITAL N}") or 4)//4]

Note the elegance of using the word LEN across two string literals
(because string literals are fast) as a means of clearly describing
what we are doing - an optimization of the built-in len() function.

ChrisA

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Thread

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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