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Groups > comp.lang.python > #48785
| Date | 2013-06-20 12:43 +0100 |
|---|---|
| From | MRAB <python@mrabarnett.plus.com> |
| Subject | Re: A few questiosn about encoding |
| References | (5 earlier) <51b90ead$0$29997$c3e8da3$5496439d@news.astraweb.com> <kpbnmg$qvk$2@news.ntua.gr> <51b9708b$0$29872$c3e8da3$5496439d@news.astraweb.com> <77ba6b16-4b1d-47a6-9b9b-5af45335c4fe@googlegroups.com> <51c2a089$0$29973$c3e8da3$5496439d@news.astraweb.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.3620.1371728614.3114.python-list@python.org> (permalink) |
On 20/06/2013 07:26, Steven D'Aprano wrote: > On Wed, 19 Jun 2013 18:46:59 -0700, Rick Johnson wrote: > >> On Thursday, June 13, 2013 2:11:08 AM UTC-5, Steven D'Aprano wrote: >> >>> Gah! That's twice I've screwed that up. Sorry about that! >> >> Yeah, and your difficulty explaining the Unicode implementation reminds >> me of a passage from the Python zen: >> >> "If the implementation is hard to explain, it's a bad idea." > > The *implementation* is easy to explain. It's the names of the encodings > which I get tangled up in. > You're off by one below! > > ASCII: Supports exactly 127 code points, each of which takes up exactly 7 > bits. Each code point represents a character. > 128 codepoints. > Latin-1, Latin-2, MacRoman, MacGreek, ISO-8859-7, Big5, Windows-1251, and > about a gazillion other legacy charsets, all of which are mutually > incompatible: supports anything from 127 to 65535 different code points, > usually under 256. > 128 to 65536 codepoints. > UCS-2: Supports exactly 65535 code points, each of which takes up exactly > two bytes. That's fewer than required, so it is obsoleted by: > 65536 codepoints. etc. > UTF-16: Supports all 1114111 code points in the Unicode charset, using a > variable-width system where the most popular characters use exactly two- > bytes and the remaining ones use a pair of characters. > > UCS-4: Supports exactly 4294967295 code points, each of which takes up > exactly four bytes. That is more than needed for the Unicode charset, so > this is obsoleted by: > > UTF-32: Supports all 1114111 code points, using exactly four bytes each. > Code points outside of the range 0 through 1114111 inclusive are an error. > > UTF-8: Supports all 1114111 code points, using a variable-width system > where popular ASCII characters require 1 byte, and others use 2, 3 or 4 > bytes as needed. > > > Ignoring the legacy charsets, only UTF-16 is a terribly complicated > implementation, due to the surrogate pairs. But even that is not too bad. > The real complication comes from the interactions between systems which > use different encodings, and that's nothing to do with Unicode. > >
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Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 00:13 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 09:09 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 07:11 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 10:42 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 17:58 +1000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 11:08 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 18:20 +1000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 12:41 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 11:49 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 17:19 +0300
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 11:00 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 09:59 +0300
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 20:14 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 16:58 +0300
Re: A few questiosn about encoding Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-14 11:21 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 18:26 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-15 03:03 +1000
Re: A few questiosn about encoding Walter Hurry <walterhurry@lavabit.com> - 2013-06-14 23:32 +0000
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-15 10:26 +1000
Re: A few questiosn about encoding Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-15 06:34 +0000
Re: A few questiosn about encoding Grant Edwards <invalid@invalid.invalid> - 2013-06-15 14:44 +0000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 17:49 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-15 15:30 +0000
Re: A few questiosn about encoding Roy Smith <roy@panix.com> - 2013-06-15 10:59 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 18:14 +0300
Re: A few questiosn about encoding Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-15 11:35 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 22:26 +0300
Re: A few questiosn about encoding Benjamin Schollnick <benjamin@schollnick.net> - 2013-06-15 16:35 -0400
Re: A few questiosn about encoding Chris “Kwpolska” Warrick <kwpolska@gmail.com> - 2013-06-16 15:45 +0200
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 09:36 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 10:49 +0300
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 10:22 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 11:37 +0300
Don't feed the troll... (was: Re: A few questiosn about encoding) Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 11:06 +0200
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 12:32 +0300
Re: Don't feed the troll... Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 13:09 +0200
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:36 +0300
Re: Don't feed the troll... Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-14 08:44 -0400
Re: Don't feed the troll... Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 15:25 +0200
Re: Don't feed the troll... Neil Cerutti <neilc@norwich.edu> - 2013-06-14 15:54 +0000
Re: Don't feed the troll... Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 12:15 +0200
Re: Don't feed the troll... Guy Scree <nobody@nowhere.com> - 2013-06-14 18:50 -0400
Re: Don't feed the troll... Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-15 06:31 +0000
Re: Don't feed the troll... Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-15 13:04 -0400
Re: Don't feed the troll... Guy Scree <nobody@nowhere.com> - 2013-06-17 16:15 -0400
Re: Don't feed the troll... Chris Angelico <rosuav@gmail.com> - 2013-06-18 07:46 +1000
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 20:19 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:41 +0300
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 11:20 +0100
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) rusi <rustompmody@gmail.com> - 2013-06-14 04:51 -0700
Re: Don't feed the help-vampire rusi <rustompmody@gmail.com> - 2013-06-14 05:09 -0700
Re: Don't feed the help-vampire Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 14:31 +0200
Re: Don't feed the help-vampire Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-14 10:51 -0600
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:50 +0300
Re: Don't feed the troll... Zero Piraeus <schesis@gmail.com> - 2013-06-14 09:33 -0400
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:45 +0300
Re: Don't feed the troll... Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 14:58 +0200
Re: Don't feed the troll... Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 14:25 +0100
Re: Don't feed the troll... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-14 17:12 +0100
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 12:50 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:59 +0300
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 15:52 +0200
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-15 10:28 +1000
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-17 08:49 +0200
Re: Don't feed the troll... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-14 12:57 +0100
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 13:13 -0400
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Chris Angelico <rosuav@gmail.com> - 2013-06-15 03:31 +1000
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Grant Edwards <invalid@invalid.invalid> - 2013-06-14 19:40 +0000
Re: Don't feed the troll "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 13:56 -0400
Re: Don't feed the troll Tim Chase <python.list@tim.thechases.com> - 2013-06-14 14:00 -0500
Re: Don't feed the troll "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 15:17 -0400
Re: Don't feed the troll... Ben Finney <ben+python@benfinney.id.au> - 2013-06-15 10:42 +1000
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-19 18:46 -0700
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-20 06:26 +0000
Re: A few questiosn about encoding MRAB <python@mrabarnett.plus.com> - 2013-06-20 12:43 +0100
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-20 09:27 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 02:37 +1000
Re: A few questiosn about encoding MRAB <python@mrabarnett.plus.com> - 2013-06-20 18:17 +0100
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-23 08:51 -0700
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 16:30 +0000
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-25 13:16 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 03:21 +1000
Re: A few questiosn about encoding Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-20 20:43 +0100
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-20 06:40 -0700
Re: A few questiosn about encoding Andrew Berg <robotsondrugs@gmail.com> - 2013-06-20 09:04 -0500
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-20 08:12 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 01:26 +1000
Re: A few questiosn about encoding Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-20 20:25 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 01:28 +1000
Re: A few questiosn about encoding Andreas Perstinger <andipersti@gmail.com> - 2013-06-20 19:08 +0200
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