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Groups > comp.lang.python > #48070

Re: A few questiosn about encoding

From Nick the Gr33k <support@superhost.gr>
Newsgroups comp.lang.python
Subject Re: A few questiosn about encoding
Date 2013-06-14 09:59 +0300
Organization National Technical University of Athens, Greece
Message-ID <kpef1e$p37$3@news.ntua.gr> (permalink)
References <kpcke3$28k2$1@news.ntua.gr> <mailman.3242.1371171652.3114.python-list@python.org>

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On 14/6/2013 4:00 πμ, Cameron Simpson wrote:
> On 13Jun2013 17:19, Nikos as SuperHost Support <support@superhost.gr> wrote:
> | A code-point and the code-point's ordinal value are associated into
> | a Unicode charset. They have the so called 1:1 mapping.
> |
> | So, i was under the impression that by encoding the code-point into
> | utf-8 was the same as encoding the code-point's ordinal value into
> | utf-8.
> |
> | So, now i believe they are two different things.
> | The code-point *is what actually* needs to be encoded and *not* its
> | ordinal value.
>
> Because there is a 1:1 mapping, these are the same thing: a code
> point is directly _represented_ by the ordinal value, and the ordinal
> value is encoded for storage as bytes.

So, you are saying that:

chr(16474).encode('utf-8')   #being the code-point encoded

ord(chr(16474)).encode('utf-8')     #being the code-point's ordinal 
encoded which gives an error.

that shows us that a character is what is being be encoded to utf-8 but 
the character's ordinal cannot.

So, whay you say "....and the ordinal value is encoded for storage as 
bytes." ?


> | > The leading 0b is just syntax to tell you "this is base 2, not base 8
> | > (0o) or base 10 or base 16 (0x)". Also, leading zero bits are dropped.
> |
> | But byte objects are represented as '\x' instead of the
> | aforementioned '0x'. Why is that?
>
> You're confusing a "string representation of a single number in
> some base (eg 2 or 16)" with the "string-ish representation of a
> bytes object".

 >>> bin(16474)
'0b100000001011010'
that is a binary format string representation of number 16474, yes?

 >>> hex(16474)
'0x405a'
that is a hexadecimal format string representation of number 16474, yes?

WHILE:

b'abc\x1b\n' = a string representation of a byte, which in turn is a 
series of integers, so that makes this a string representation of 
integers, is this correct?

\x1b = ESC character

\ = for seperating bytes
x = to flag that the following bytes are going to be represented as hex 
values? whats exactly 'x' means here? character perhaps?

Still its not clear into my head what the difference of '0x1b' and 
'\x1b' is:

i think:
0x1b = an integer represented in hex format

\x1b = a character represented in hex format

id this true?




> | How can i view this byte's object representation as hex() or as bin()?
>
> See above. A bytes is a _sequence_ of values. hex() and bin() print
> individual values in hexadecimal or binary respectively.

 >>> for value in b'\x97\x98\x99\x27\x10':
...     print(value, hex(value), bin(value))
...
151 0x97 0b10010111
152 0x98 0b10011000
153 0x99 0b10011001
39 0x27 0b100111
16 0x10 0b10000


 >>> for value in b'abc\x1b\n':
...     print(value, hex(value), bin(value))
...
97 0x61 0b1100001
98 0x62 0b1100010
99 0x63 0b1100011
27 0x1b 0b11011
10 0xa 0b1010


Why these two give different values when printed?
-- 
What is now proved was at first only imagined!

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Thread

A few questiosn about encoding Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 03:44 -0700
  Re: A few questiosn about encoding Fábio Santos <fabiosantosart@gmail.com> - 2013-06-09 13:18 +0100
  Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-09 18:01 +0100
  Re: A few questiosn about encoding Chris “Kwpolska” Warrick <kwpolska@gmail.com> - 2013-06-09 19:12 +0200
    Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-12 09:09 +0000
      Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-12 09:24 +0000
        Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-12 14:23 +0300
          Re: A few questiosn about encoding Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2013-06-12 14:52 +0200
          Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-12 21:30 +0100
            Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 01:40 +0000
              Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 12:01 +1000
                Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-13 11:02 +0100
            Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 09:21 +0300
              Re: A few questiosn about encoding jmfauth <wxjmfauth@gmail.com> - 2013-06-12 23:28 -0700
              Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 16:48 +1000
          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
        Re: A few questiosn about encoding Dave Angel <davea@davea.name> - 2013-06-12 08:43 -0400
      Re: A few questiosn about encoding Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-13 18:46 -0400
        Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 08:34 +0300
          Re: A few questiosn about encoding Zero Piraeus <schesis@gmail.com> - 2013-06-14 02:00 -0400
            Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 10:28 +0300

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