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Re: Python usage numbers

References (8 earlier) <jh9d7i$d6q$1@dough.gmane.org> <mailman.5739.1329084873.27778.python-list@python.org> <roy-E2270B.17273412022012@news.panix.com> <4f384b6e$0$29986$c3e8da3$5496439d@news.astraweb.com> <4F38536A.2030208@davea.name>
Date 2012-02-13 11:59 +1100
Subject Re: Python usage numbers
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.5750.1329094801.27778.python-list@python.org> (permalink)

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On Mon, Feb 13, 2012 at 11:03 AM, Dave Angel <d@davea.name> wrote:
> On 02/12/2012 06:29 PM, Steven D'Aprano wrote:
>> I think you mean 4 times as many bytes as characters. Unless you have 32
>> bit bytes :)
>>
>>
> Until you have 32 bit bytes, you'll continue to have encodings, even if only
> a couple of them.

The advantage, though, is that you can always know how many bytes to
read for X characters. In ASCII, you allocate 80 bytes of storage and
you can store 80 characters. In UTF-8, if you want an 80-character
buffer, you can probably get away with allocating 240 characters...
but maybe not. In UTF-32, it's easy - just allocate 320 bytes and you
know you can store them. Also, you know exactly where the 17th
character is; in UTF-8, you have to count. That's a huge advantage for
in-memory strings; but is it useful on disk, where (as likely as not)
you're actually looking for lines, which you still have to scan for?
I'm thinking not, so it makes sense to use a smaller disk image than
UTF-32 - less total bytes means less sectors to read/write, which
translates fairly directly into performance.

ChrisA

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Thread

Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-12 12:28 +1100
  Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 02:23 +0000
    Re: Python usage numbers Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-11 18:36 -0800
      Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-12 15:38 +1100
        Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 05:51 +0000
          Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-12 17:08 +1100
          Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 10:48 -0500
            Re: Python usage numbers Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-02-12 11:47 -0500
              Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 12:11 -0500
                Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 22:49 +0000
          Re: Python usage numbers Dan Sommers <dan@tombstonezero.net> - 2012-02-12 15:55 +0000
          Re: Python usage numbers rusi <rustompmody@gmail.com> - 2012-02-12 08:50 -0800
            Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 12:21 -0500
            Re: Python usage numbers Nick Dokos <nicholas.dokos@hp.com> - 2012-02-12 12:36 -0500
              entering unicode  (was Python usage numbers) rusi <rustompmody@gmail.com> - 2012-02-12 19:09 -0800
                Re: entering unicode  (was Python usage numbers) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-19 03:44 +0000
                Re: entering unicode (was Python usage numbers) rusi <rustompmody@gmail.com> - 2012-02-19 00:52 -0800
            How do you Unicode proponents type your non-ASCII characters? (was: Python usage numbers) Ben Finney <ben+python@benfinney.id.au> - 2012-02-13 09:43 +1100
            Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 22:56 +0000
        Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 10:13 -0500
          Re: Python usage numbers Terry Reedy <tjreedy@udel.edu> - 2012-02-12 17:07 -0500
            Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 17:22 -0500
          Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-13 09:14 +1100
            Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 17:27 -0500
              Re: Python usage numbers Dave Angel <davea@dejaviewphoto.com> - 2012-02-12 17:40 -0500
              Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 23:29 +0000
                Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 18:41 -0500
                Re: Python usage numbers Dave Angel <d@davea.name> - 2012-02-12 19:03 -0500
                Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-13 11:59 +1100
                Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 20:11 -0500
          Re: Python usage numbers Christian Heimes <lists@cheimes.de> - 2012-02-13 01:00 +0100
          Re: Python usage numbers Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-02-12 21:37 -0500
          Re: Python usage numbers Terry Reedy <tjreedy@udel.edu> - 2012-02-12 22:09 -0500
            Re: Python usage numbers Roy Smith <roy@panix.com> - 2012-02-12 22:57 -0500
              Re: Python usage numbers Ben Finney <ben+python@benfinney.id.au> - 2012-02-13 15:19 +1100
                Re: Python usage numbers Andrew Berg <bahamutzero8825@gmail.com> - 2012-02-13 12:26 -0600
            Re: Python usage numbers jmfauth <wxjmfauth@gmail.com> - 2012-02-14 00:00 -0800
      Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 06:10 +0000
        Re: Python usage numbers Andrew Berg <bahamutzero8825@gmail.com> - 2012-02-12 01:05 -0600
          Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 09:12 +0000
            Re: Python usage numbers Andrew Berg <bahamutzero8825@gmail.com> - 2012-02-12 05:11 -0600
              Re: Python usage numbers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-12 22:30 +0000
                Re: Python usage numbers Dave Angel <d@davea.name> - 2012-02-12 17:50 -0500
            Re: Python usage numbers Peter Pearson <ppearson@nowhere.invalid> - 2012-02-12 17:58 +0000
        Re: Python usage numbers Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-12 20:48 -0800
          Re: Python usage numbers Chris Angelico <rosuav@gmail.com> - 2012-02-13 16:03 +1100
          OT: Entitlements [was Re: Python usage numbers] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-13 08:05 +0000
            Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-13 08:01 -0800
              Re: OT: Entitlements [was Re: Python usage numbers] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-13 16:12 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-13 08:27 -0800
              Re: OT: Entitlements [was Re: Python usage numbers] Ian Kelly <ian.g.kelly@gmail.com> - 2012-02-13 11:38 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-13 13:01 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-14 08:27 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-13 21:46 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-14 00:19 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-13 17:07 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Ian Kelly <ian.g.kelly@gmail.com> - 2012-02-13 18:29 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-17 17:13 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-18 13:13 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-18 02:39 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Ian Kelly <ian.g.kelly@gmail.com> - 2012-02-18 00:28 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-18 07:02 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-18 16:15 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-18 10:34 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] random joe <pywin32@gmail.com> - 2012-02-18 10:49 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-02-26 12:14 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Terry Reedy <tjreedy@udel.edu> - 2012-02-18 04:16 -0500
                Re: OT: Entitlements [was Re: Python usage numbers] John O'Hagan <research@johnohagan.com> - 2012-02-14 19:41 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-14 16:21 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-15 11:44 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-14 17:26 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] John O'Hagan <research@johnohagan.com> - 2012-02-15 19:56 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-15 07:04 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-15 15:18 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-15 08:27 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-15 17:16 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Ian Kelly <ian.g.kelly@gmail.com> - 2012-02-15 09:46 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-02-26 12:44 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-26 12:35 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-27 07:50 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-26 14:32 -0800
                Re: OT: Entitlements Ben Finney <ben+python@benfinney.id.au> - 2012-02-27 07:46 +1100
              Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-14 07:47 +1100
              Re: OT: Entitlements [was Re: Python usage numbers] Michael Torrie <torriem@gmail.com> - 2012-02-13 14:46 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-13 16:39 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Michael Torrie <torriem@gmail.com> - 2012-02-13 18:36 -0700
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-14 12:37 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-17 17:37 -0800
              Re: OT: Entitlements [was Re: Python usage numbers] Tim Wintle <tim.wintle@teamrubber.com> - 2012-02-13 16:41 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-14 16:40 -0800
                RE: OT: Entitlements [was Re: Python usage numbers] "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-02-17 20:09 +0000
              Re: OT: Entitlements [was Re: Python usage numbers] Duncan Booth <duncan.booth@invalid.invalid> - 2012-02-14 11:31 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-02-14 07:06 -0500
                Re: OT: Entitlements [was Re: Python usage numbers] Rick Johnson <rantingrickjohnson@gmail.com> - 2012-02-14 16:48 -0800
                Re: OT: Entitlements [was Re: Python usage numbers] Chris Angelico <rosuav@gmail.com> - 2012-02-15 12:32 +1100
                Re: OT: Entitlements [was Re: Python usage numbers] Duncan Booth <duncan.booth@invalid.invalid> - 2012-02-15 09:47 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Arnaud Delobelle <arnodel@gmail.com> - 2012-02-15 09:58 +0000
                Re: OT: Entitlements [was Re: Python usage numbers] Duncan Booth <duncan.booth@invalid.invalid> - 2012-02-15 10:04 +0000
                Kill files [was Re: OT: Entitlements [was Re: Python usage numbers]] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-02-15 10:27 +0000
                Re: Kill files [was Re: OT: Entitlements [was Re: Python usage numbers]] Ethan Furman <ethan@stoneleaf.us> - 2012-02-15 11:29 -0800
              Re: OT: Entitlements [was Re: Python usage numbers] rusi <rustompmody@gmail.com> - 2012-02-14 04:56 -0800
              Re: OT: Entitlements [was Re: Python usage numbers] Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-02-14 09:37 -0500
    Re: Python usage numbers Matej Cepl <mcepl@redhat.com> - 2012-02-12 09:14 +0100
      Re: Python usage numbers Matej Cepl <mcepl@redhat.com> - 2012-02-12 09:26 +0100
        Re: Python usage numbers Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-02-12 12:11 +0000
          Re: Python usage numbers alister <alister.ware@ntlworld.com> - 2012-02-12 18:55 +0000
            Re: Python usage numbers jmfauth <wxjmfauth@gmail.com> - 2012-02-12 11:52 -0800
              French and IDLE on Windows  (was Re: Python usage numbers) Terry Reedy <tjreedy@udel.edu> - 2012-02-12 18:30 -0500
        Re: Python usage numbers Anssi Saari <as@sci.fi> - 2012-02-15 11:56 +0200

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