Re: Changing filenames from Greeklish => Greek (subprocess complain)

References	<5b0d3d7c-e3a4-436d-a55f-26bd40064fd5@googlegroups.com> <mailman.2911.1370769172.3114.python-list@python.org> <8471f19b-e21a-4859-9842-92a97d75a840@googlegroups.com>
Date	2013-06-09 13:01 -0700
Subject	Re: Changing filenames from Greeklish => Greek (subprocess complain)
From	Benjamin Kaplan <benjamin.kaplan@case.edu>
Newsgroups	comp.lang.python
Message-ID	<mailman.2934.1370808466.3114.python-list@python.org> (permalink)

Show all headers | View raw

On Sun, Jun 9, 2013 at 2:20 AM, Νικόλαος Κούρας <nikos.gr33k@gmail.com> wrote:
> Τη Κυριακή, 9 Ιουνίου 2013 12:12:36 μ.μ. UTC+3, ο χρήστης Cameron Simpson έγραψε:
>> On 09Jun2013 02:00, =?utf-8?B?zp3Or866zr/PgiDOk866z4EzM866?= <nikos.gr33k@gmail.com> wrote:
>>
>> | Steven wrote:
>>
>> | >> Since 1 byte can hold up to 256 chars, why not utf-8 use 1-byte for
>>
>> | >> values up to 256?
>>
>> |
>>
>> | >Because then how do you tell when you need one byte, and when you need
>>
>> | >two? If you read two bytes, and see 0x4C 0xFA, does that mean two
>>
>> | >characters, with ordinal values 0x4C and 0xFA, or one character with
>>
>> | >ordinal value 0x4CFA?
>>
>> |
>>
>> | I mean utf-8 could use 1 byte for storing the 1st 256 characters. I meant up to 256, not above 256.
>>
>>
>>
>> Then it would not be UTF-8. UTF-8 will encode an Unicode codepoint. Your >suggestion will not.
>
> I dont follow.
>

The point in the UTF formats is that they can encode any of the 1.1
million codepoints available in Unicode. Your suggestion can only
encode 256 code points. We have that encoding already- it's called
Latin-1 and it can't encode any of your Greek characters (hence why
ISO-8859-7 exists, which can encode the Greek characters but not the
Latin ones).

If you were to use the whole byte to store the first 256 characters,
you wouldn't be able to store character number 256 because the
computer wouldn't be able to tell the difference between character 257
(0x01 0x01) and two chr(1)s. UTF-8 gets around this by reserving the
top bit as a "am I part of a multibyte sequence" flag,

>> | >> UTF-8 and UTF-16 and UTF-32
>>
>> | >> I though the number beside of UTF- was to declare how many bits the
>>
>> | >> character set was using to store a character into the hdd, no?
>>
>> |
>>
>> | >Not exactly, but close. UTF-32 is completely 32-bit (4 byte) values.
>>
>> | >UTF-16 mostly uses 16-bit values, but sometimes it combines two 16-bit
>>
>> | >values to make a surrogate pair.
>>
>> |
>>
>> | A surrogate pair is like itting for example Ctrl-A, which means is a combination character that consists of 2 different characters?
>>
>> | Is this what a surrogate is? a pari of 2 chars?
>>
>>
>>
>> Essentially. The combination represents a code point.
>>
>>
>>
>> | >UTF-8 uses 8-bit values, but sometimes
>>
>> | >it combines two, three or four of them to represent a single code-point.
>>
>> |
>>
>> | 'a' to be utf8 encoded needs 1 byte to be stored ? (since ordinal = 65)
>>
>> | 'α΄' to be utf8 encoded needs 2 bytes to be stored ? (since ordinal is > 127 )
>>
>> | 'a chinese ideogramm' to be utf8 encoded needs 4 byte to be stored ? (since ordinal >  65000 )
>>
>> |
>>
>> | The amount of bytes needed to store a character solely depends on the character's ordinal value in the Unicode table?
>>
>>
>>
>> Essentially. You can read up on the exact process in Wikipedia or the Unicode Standard.
>
>
>
> When you say essentially means you agree with my statements?
> --

In UTF-8 or UTF-16, the number of bytes required for the character is
dependent on its code point, yes. That isn't the case for UTF-32,
where every character uses exactly four bytes.

Thread

Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-07 18:53 +1000
  Re: Changing filenames from Greeklish => Greek (subprocess complain) alex23 <wuwei23@gmail.com> - 2013-06-07 02:41 -0700
  Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-07 04:53 -0700
    Re: Changing filenames from Greeklish => Greek (subprocess complain) MRAB <python@mrabarnett.plus.com> - 2013-06-07 15:29 +0100
      Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-07 11:52 -0700
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Zero Piraeus <schesis@gmail.com> - 2013-06-07 15:31 -0400
        Re: Changing filenames from Greeklish => Greek (subprocess complain) MRAB <python@mrabarnett.plus.com> - 2013-06-07 21:45 +0100
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Zero Piraeus <schesis@gmail.com> - 2013-06-07 19:24 -0400
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-08 12:52 +1000
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-07 23:49 -0700
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Chris Angelico <rosuav@gmail.com> - 2013-06-08 16:58 +1000
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-08 07:26 +0000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Chris Angelico <rosuav@gmail.com> - 2013-06-08 17:40 +1000
            Re: Changing filenames from Greeklish => Greek (subprocess complain) MRAB <python@mrabarnett.plus.com> - 2013-06-08 17:32 +0100
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-08 09:53 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-08 10:35 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) MRAB <python@mrabarnett.plus.com> - 2013-06-08 18:48 +0100
    Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-07 15:33 +0000
    Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-08 12:49 +1000
    Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-08 21:01 +0300
      Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-08 19:01 +0000
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-08 14:14 -0700
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-09 08:32 +1000
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 07:46 +0300
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 06:25 +0000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-09 18:02 +1000
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:03 -0700
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-08 14:21 -0700
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Chris Angelico <rosuav@gmail.com> - 2013-06-09 08:10 +1000
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 01:11 -0700
    Re: Changing filenames from Greeklish => Greek (subprocess complain) Chris Angelico <rosuav@gmail.com> - 2013-06-09 04:47 +1000
      Re: Changing filenames from Greeklish => Greek (subprocess complain) nagia.retsina@gmail.com - 2013-06-08 22:09 -0700
        Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 06:45 +0000
          Re: Changing filenames from Greeklish => Greek (subprocess complain) nagia.retsina@gmail.com - 2013-06-09 00:00 -0700
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 08:15 +0000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:14 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 03:32 -0700
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-09 19:16 +1000
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 12:36 +0000
                Re: Changing filenames from Greeklish => Greek (subprocess complain) nagia.retsina@gmail.com - 2013-06-09 10:25 -0700
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Lele Gaifax <lele@metapensiero.it> - 2013-06-09 10:55 +0200
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:08 -0700
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Lele Gaifax <lele@metapensiero.it> - 2013-06-09 11:20 +0200
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:38 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Andreas Perstinger <andipersti@gmail.com> - 2013-06-09 14:24 +0200
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 13:13 +0000
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-06-09 13:05 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:42 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 03:37 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Larry Hudson <orgnut@yahoo.com> - 2013-06-10 00:51 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-10 01:11 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Larry Hudson <orgnut@yahoo.com> - 2013-06-11 00:20 -0700
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 11:50 +0000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 05:18 -0700
          Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:00 -0700
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Cameron Simpson <cs@zip.com.au> - 2013-06-09 19:12 +1000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 02:20 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-06-09 13:01 -0700
            Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-09 12:31 +0000
              Re: Changing filenames from Greeklish => Greek (subprocess complain) nagia.retsina@gmail.com - 2013-06-10 00:10 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Andreas Perstinger <andipersti@gmail.com> - 2013-06-10 10:15 +0200
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-10 01:54 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-10 02:59 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Andreas Perstinger <andipersti@gmail.com> - 2013-06-10 12:42 +0200
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-10 11:59 +0000
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-10 07:27 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) jmfauth <wxjmfauth@gmail.com> - 2013-06-10 12:48 -0700
                Re: Changing filenames from Greeklish => Greek (subprocess complain) Ned Batchelder <ned@nedbatchelder.com> - 2013-06-10 13:28 -0700

csiph-web