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Groups > comp.lang.python > #104330

Re: Pyhon 2.x or 3.x, which is faster?

From BartC <bc@freeuk.com>
Newsgroups comp.lang.python
Subject Re: Pyhon 2.x or 3.x, which is faster?
Date 2016-03-08 11:53 +0000
Organization A noiseless patient Spider
Message-ID <nbmeaf$r45$1@dont-email.me> (permalink)
References (8 earlier) <mailman.43.1457377845.10335.python-list@python.org> <nbknir$avu$1@dont-email.me> <mailman.49.1457383632.10335.python-list@python.org> <nbkvq2$j5s$1@dont-email.me> <56de3513$0$1621$c3e8da3$5496439d@news.astraweb.com>

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On 08/03/2016 02:12, Steven D'Aprano wrote:
> On Tue, 8 Mar 2016 09:39 am, BartC wrote:

>> I'm using it because this kind of file reading in Python is a mess. If I
>> do a read, will I get a string, a byte sequence object, a byte-array, or
>> array-array, or what?
>
> Calling it "a mess" is an exaggeration. There is a change between Python 2
> and 3:
>
> - in Python 2, reading from a file gives you bytes, that is, the
> so-called "str" type, not unicode;
>
> - in Python 3, reading from a file in binary mode gives you bytes, that is,
> the "bytes" type; reading in text mode gives you a string, the "str" type.
>
> How is this a mess?

               Python 2     Python 3

Text mode     'str'          'str'
Binary mode   'bytes'        'str'

For certain file formats, text mode can't be used because byte values 
such as 10 could be expanded to the two bytes 13,10 on some systems.

So binary needs to be used. But Py2 and Py3 return different results; 
and indexing a bytes object gives you an int, a str object gives you a str.

If you pass a file-handle to a function, that function can't just do a 
read from that handle without considering whether the file might be in 
text or binary mode, or whether it's running under Py2 or Py3.

And I think someone pointed out the difference between 'bytes', 
'bytearray' and 'array.array', but I can't find that post at the minute.

-- 
bartc

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Thread

Pyhon 2.x or 3.x, which is faster? Tony van der Hoff <tony@vanderhoff.org> - 2016-03-06 11:34 +0000
  Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-07 01:41 +1100
    Re: Pyhon 2.x or 3.x, which is faster? Tony van der Hoff <tony@vanderhoff.org> - 2016-03-07 10:45 +0000
    Re: Pyhon 2.x or 3.x, which is faster? Andrew Jaffe <a.h.jaffe@gmail.com> - 2016-03-07 11:54 +0000
    Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 17:33 -0500
  Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 11:02 +0000
    Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-07 13:11 +0200
      Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 11:38 +0000
        Re: Pyhon 2.x or 3.x, which is faster? Fabien <fabien.maussion@gmail.com> - 2016-03-07 13:19 +0100
          Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 13:25 +0000
            Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 02:31 +1100
              Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 18:34 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 06:10 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 20:19 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 07:47 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-07 22:39 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 10:40 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 00:22 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 00:43 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 11:45 +1100
                Re: Pyhon 2.x or 3.x, which is faster? MRAB <python@mrabarnett.plus.com> - 2016-03-08 00:47 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-03-07 20:29 -0500
                Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 22:51 -0500
                Re: Pyhon 2.x or 3.x, which is faster? Michael Torrie <torriem@gmail.com> - 2016-03-08 17:34 -0700
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 13:01 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-09 11:38 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 11:05 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:00 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 01:12 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:47 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 02:45 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:09 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 16:09 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 19:15 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 20:44 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 22:38 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 10:59 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 08:40 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 12:02 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 21:13 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 23:14 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-09 23:35 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 00:58 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 12:28 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 07:30 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 11:50 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 12:15 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 12:47 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 00:08 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 14:22 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 19:26 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-11 16:29 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-11 18:57 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-11 21:59 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-11 22:24 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-12 16:59 +1100
                Re: Pyhon 2.x or 3.x, which is faster? alister <alister.ware@ntlworld.com> - 2016-03-12 10:06 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-12 10:31 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-12 10:51 +0000
                Re: Pyhon 2.x or 3.x, which is faster? alister <alister.ware@ntlworld.com> - 2016-03-12 15:36 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-13 14:22 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-12 10:34 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-12 21:40 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 07:07 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-11 16:06 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 16:36 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 13:18 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-11 00:30 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-10 13:46 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 18:43 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 18:55 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 12:59 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 12:19 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 10:38 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 23:48 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 11:03 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-10 02:38 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 14:43 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 01:30 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 13:29 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-10 14:32 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 13:45 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-10 11:21 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:23 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:33 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 12:38 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:40 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 02:02 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 13:28 +1100
                Re: Pyhon 2.x or 3.x, which is faster? MRAB <python@mrabarnett.plus.com> - 2016-03-08 02:47 +0000
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:15 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-08 13:45 +0200
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 12:09 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-07 22:39 -0500
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 03:48 +0000
                What will I get when reading from a file? (was: Pyhon 2.x or 3.x, which is faster?) Ben Finney <ben+python@benfinney.id.au> - 2016-03-08 11:09 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 13:12 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 11:53 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 10:28 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 00:09 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-09 11:36 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-03-08 21:03 -0500
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 03:07 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Serhiy Storchaka <storchaka@gmail.com> - 2016-03-08 14:48 +0200
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 12:34 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-08 12:49 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Serhiy Storchaka <storchaka@gmail.com> - 2016-03-08 15:05 +0200
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-08 12:19 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 01:41 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-08 15:40 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 13:49 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 16:15 +0000
                Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-08 09:23 -0800
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-08 19:02 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 11:04 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 01:28 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 13:18 +1100
                Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-09 02:11 -0800
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 14:03 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 01:11 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 14:39 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 01:54 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:33 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 02:58 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 14:56 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:28 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 01:57 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Chris Angelico <rosuav@gmail.com> - 2016-03-10 02:04 +1100
                Re: Pyhon 2.x or 3.x, which is faster? BartC <bc@freeuk.com> - 2016-03-09 16:53 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 01:54 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-03-09 15:06 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Tim Golden <mail@timgolden.me.uk> - 2016-03-09 15:15 +0000
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 02:38 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Terry Reedy <tjreedy@udel.edu> - 2016-03-09 10:42 -0500
                Re: Pyhon 2.x or 3.x, which is faster? wxjmfauth@gmail.com - 2016-03-09 09:04 -0800
                Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-09 08:08 +0200
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-09 22:52 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Marko Rauhamaa <marko@pacujo.net> - 2016-03-09 14:53 +0200
                Re: Pyhon 2.x or 3.x, which is faster? Steven D'Aprano <steve@pearwood.info> - 2016-03-10 03:53 +1100
                Re: Pyhon 2.x or 3.x, which is faster? Michael Torrie <torriem@gmail.com> - 2016-03-08 17:42 -0700
        Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-08 02:53 +0000
    Re: Pyhon 2.x or 3.x, which is faster? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-07 19:02 +0000

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