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

Newsgroups	comp.lang.python
Date	2013-06-09 03:37 -0700
References	(5 earlier) <51b4249d$0$30001$c3e8da3$5496439d@news.astraweb.com> <mailman.2910.1370768144.3114.python-list@python.org> <9a0ea98b-f37b-48da-9933-e2caf6fdfdff@googlegroups.com> <mailman.2913.1370769662.3114.python-list@python.org> <4500f6f7-2296-4320-b6b9-dbc71c732500@googlegroups.com>
Message-ID	<82414c38-cec0-404d-8d5d-435fed0750c7@googlegroups.com> (permalink)
Subject	Re: Changing filenames from Greeklish => Greek (subprocess complain)
From	Νικόλαος Κούρας <nikos.gr33k@gmail.com>

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I k nwo i have been a pain in the ass these days but this is the lats explanation i want from you, just to understand it completely.

>> 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.


>> 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?


>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?


>UTF-8 solves this problem by reserving some values to mean "this byte, on 
>its own", and others to mean "this byte, plus the next byte, together", 
>and so forth, up to four bytes.

Some of the utf-8 bits that are used to represent a character's ordinal value are actually been also used to seperate or join the ordinal values themselves?
Can you give an example please? How there are beign seperated?


>Computers are digital and work with numbers.


So character 'A' <-> 65 (in decimal uses in charset's table)  <-> 01011100 (as binary stored in disk) <-> 0xEF (as hex, when we open the file with a hex editor)

Is this how the thing works? (above values are fictional)

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

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