Re: Objects in Python

Date	2012-08-23 12:28 +0100
From	MRAB <python@mrabarnett.plus.com>
Subject	Re: Objects in Python
References	(3 earlier) <gsSdnaYuqqabhqjNnZ2dnUVZ8jmdnZ2d@bt.com> <87d32i1ntc.fsf@benfinney.id.au> <mailman.3693.1345697563.4697.python-list@python.org> <5035d3e4$0$1645$c3e8da3$76491128@news.astraweb.com> <qotpq6irnjn.fsf@ruuvi.it.helsinki.fi>
Newsgroups	comp.lang.python
Message-ID	<mailman.3711.1345721330.4697.python-list@python.org> (permalink)

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On 23/08/2012 09:59, Jussi Piitulainen wrote:
> Steven D'Aprano writes:
>> On Wed, 22 Aug 2012 23:49:17 -0500, Evan Driscoll wrote:
>>
>> > On 8/22/2012 18:58, Ben Finney wrote:
>> >> You haven't discovered anything about types; what you have
>> >> discovered is that Python name bindings are not variables.
>> >>
>> >> In fact, Python doesn't have variables – not as C or Java
>> >> programmers would understand the term. What it has instead are
>> >> references to objects (with names as one kind of reference).
>> >
>> > OK, I've seen this said a few times, and I have to ask: what do
>> > you mean by this? I consider myself pretty decent at Python and
>> > other languages, and I really don't get it.
>>
>> I think the point that Ben would like to make is that while "name
>> binding" is a specific kind of "variable", the word "variable" comes
>> with too much baggage from the old-school C, Pascal etc. style of
>> variables- are-named-memory-locations. Most of the time, the
>> differences are unimportant, but when they are important, if your
>> mental image is that Python "variables" (name bindings) are like C
>> or Pascal "variables" (memory locations), you're going to get
>> confused.
>
> I don't get it either. To me the python-has-no-variables campaigners
> seem confused. As far as I can see, Python can be seen in terms of
> variables bound to (locations containing) values perfectly well, in a
> way that should be quite familiar to people who come from Java (or
> Lisp, Scheme like me).
>
[snip]
In Java a variable exists even when it has not been assigned a value.
In Python, on the other hand, the basic model is that a 'variable'
doesn't exist until it has been bound to an value (although, for
efficiency reasons, that's not entirely true, because at compile time
CPython will identify the local variables in a function and allocate a
'slot' for it).

Thread

Objects in Python shaun <shaun.wiseman91@gmail.com> - 2012-08-22 07:13 -0700
  Re: Objects in Python Joel Goldstick <joel.goldstick@gmail.com> - 2012-08-22 10:31 -0400
  Re: Objects in Python Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-08-22 17:31 +0300
  Re: Objects in Python Peter Otten <__peter__@web.de> - 2012-08-22 16:36 +0200
  Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 15:59 +0100
    Re: Objects in Python MRAB <python@mrabarnett.plus.com> - 2012-08-22 16:58 +0100
      Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 17:10 +0100
        Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-22 17:30 +0100
          Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 18:06 +0100
            Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-22 19:07 +0100
              Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 20:13 +0100
    Re: Objects in Python Terry Reedy <tjreedy@udel.edu> - 2012-08-22 13:01 -0400
      Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 18:46 +0100
        Re: Objects in Python Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-22 12:15 -0600
          Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 20:03 +0100
            Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-23 12:02 +1000
              Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 04:11 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-23 15:26 +1000
                Re: Objects in Python Jan Kuiken <jan.kuiken@quicknet.nl> - 2012-08-23 20:02 +0200
                Re: Objects in Python Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-23 12:17 -0600
                Re: Objects in Python Jan Kuiken <jan.kuiken@quicknet.nl> - 2012-08-23 22:43 +0200
                Re: Objects in Python 88888 Dihedral <dihedral88888@googlemail.com> - 2012-08-25 23:14 -0700
        Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-22 19:23 +0100
        Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-22 14:03 -0500
          Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-22 20:45 +0100
            Re: Objects in Python MRAB <python@mrabarnett.plus.com> - 2012-08-22 21:31 +0100
            Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-22 21:46 +0100
              Methods versus functions [was Re: Objects in Python] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 04:07 +0000
            Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-22 16:31 -0500
              Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-23 10:19 +0100
                Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-23 11:44 -0500
                Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-23 18:56 +0100
        Re: Objects in Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-23 09:58 +1000
          Re: Objects in Python Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-22 18:10 -0600
          Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-22 23:49 -0500
            Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 06:55 +0000
              Re: Objects in Python Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-08-23 11:59 +0300
                Re: Objects in Python MRAB <python@mrabarnett.plus.com> - 2012-08-23 12:28 +0100
                Re: Objects in Python Jerry Hill <malaclypse2@gmail.com> - 2012-08-23 10:43 -0400
                Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-23 12:17 -0500
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 17:56 +0000
                Variables vs names [was: Objects in Python] Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-23 14:22 -0500
                Re: Variables vs names Ben Finney <ben+python@benfinney.id.au> - 2012-08-24 10:02 +1000
                Re: Variables vs names [was: Objects in Python] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-25 02:05 +0000
                Re: Variables vs names Ben Finney <ben+python@benfinney.id.au> - 2012-08-25 15:24 +1000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-24 08:00 +1000
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-25 03:04 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-25 16:34 +1000
                Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-25 09:55 +0100
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-25 20:23 +1000
                Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-25 12:01 +0100
                Re: Objects in Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-25 15:56 -0400
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-26 09:27 +1000
                Re: Objects in Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-25 20:43 -0400
                Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-26 00:25 -0500
                Re: Variables vs names [was: Objects in Python] Chris Angelico <rosuav@gmail.com> - 2012-08-24 09:34 +1000
                Re: Objects in Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-24 09:49 +1000
                Re: Variables vs names [was: Objects in Python] Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-23 19:52 -0400
                Re: Objects in Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-23 19:54 -0400
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-24 10:01 +1000
                Re: Objects in Python Terry Reedy <tjreedy@udel.edu> - 2012-08-23 13:17 -0400
            Re: Objects in Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-24 00:16 +1000
            Re: Objects in Python Roy Smith <roy@panix.com> - 2012-08-23 20:36 -0400
              Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-24 11:34 +1000
                Re: Objects in Python alex23 <wuwei23@gmail.com> - 2012-08-23 20:17 -0700
                Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-24 04:14 -0500
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-24 10:00 +0000
                Re: Objects in Python Grant Edwards <invalid@invalid.invalid> - 2012-08-24 13:27 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-25 05:18 +1000
                Re: Re: Objects in Python Evan Driscoll <driscoll@cs.wisc.edu> - 2012-08-26 00:45 -0500
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-26 13:43 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-26 23:58 +1000
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-26 14:18 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-27 00:54 +1000
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-26 22:47 +0000
                Re: Objects in Python Roy Smith <roy@panix.com> - 2012-08-26 10:02 -0400
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-27 00:14 +1000
                Re: Objects in Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-26 16:12 -0400
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-26 23:29 +0000
                Re: Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-26 16:22 +1000
                Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-26 12:02 +0000
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-26 23:34 +1000
                Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-26 15:02 +0100
                Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-27 00:05 +1000
                Re: Objects in Python Roy Smith <roy@panix.com> - 2012-08-26 09:41 -0400
              Identity function id() [was Re: Objects in Python] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-24 10:06 +0000
          Re: Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-23 15:33 +1000
          Re: Objects in Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-23 14:30 -0400
            Re: Objects in Python Alexander Blinne <news@blinne.net> - 2012-08-24 15:23 +0200
          Re: Objects in Python Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2012-08-24 09:38 +0200
          Re: Objects in Python Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2012-08-24 10:03 +0200
        Re: Objects in Python Walter Hurry <walterhurry@lavabit.com> - 2012-08-23 01:19 +0000
          Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 04:14 +0000
            Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-23 09:10 +0100
              Re: Objects in Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-23 23:59 +1000
                Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-23 15:20 +0100
                Re: Objects in Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-24 00:24 +1000
          Re: Objects in Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-23 09:03 +0100
        Re: Objects in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 04:34 +0000
          Re: Objects in Python rusi <rustompmody@gmail.com> - 2012-08-23 10:04 -0700
  Re: Objects in Python John Gordon <gordon@panix.com> - 2012-08-22 15:03 +0000
  Re: Objects in Python shaun <shaun.wiseman91@gmail.com> - 2012-08-22 08:25 -0700
    Re: Objects in Python Chris Angelico <rosuav@gmail.com> - 2012-08-23 01:47 +1000
    Re: Objects in Python Dave Angel <d@davea.name> - 2012-08-22 11:51 -0400
    Re: Objects in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-22 17:13 +0100
    Re: Objects in Python Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-22 11:29 -0600

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