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Re: A certainl part of an if() structure never gets executed.

References (21 earlier) <kpi45d$n5$3@news.ntua.gr> <kpjm6h$4rb$1@dont-email.me> <kpjrng$hmp$1@news.ntua.gr> <kpk04c$4rb$6@dont-email.me> <kpk295$hmp$5@news.ntua.gr>
From "R. Michael Weylandt" <michael.weylandt@gmail.com>
Date 2013-06-16 11:42 +0100
Subject Re: A certainl part of an if() structure never gets executed.
Newsgroups comp.lang.python
Message-ID <mailman.3433.1371379385.3114.python-list@python.org> (permalink)

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On Sun, Jun 16, 2013 at 10:59 AM, Nick the Gr33k <support@superhost.gr> wrote:
> On 16/6/2013 12:22 μμ, Denis McMahon wrote:
>>
>> For example, in Python
>>
>> a = 6
>> b = a
>> c = 6
>>
>> a and b point to one memory location that contains the value 6
>> c points to a different memory location that contains the value 6
>
>
> I believe you are mistaken.
>
> a here is not a pointer but variable,
> which is a memory location that stores value 6.
>
> b here is a pointer. It's value is the memory location of variable a which
> stores value 6.
>
> c here is just te same as a , a variable.

Actually, y'all both might be. This is a bit CPython specific and not
mandated by the language specification.

To Nikos: please don't extrapolate from the examples below. They are a
CPython (the most common implementation of the Python language)
specific detail.

## CODE SNIPPET##
a = 6; b = a; c = 6

id(a)
id(b)
id(c)
## END CODE##

These are all the same, indicating that they all point to the "same 6"
in memory. That's a CPython specific optimization (caching small
integers) which is not guaranteed by the language and changes between
pythons and between compiles.

For example,

## CODE SNIPPET##
a = 552315251254
b = a
c =  552315251254

a is b # True _on my machine_
a is c # False _on my machine_

id(a)
id(b)
id(c)
## END CODE##

Note that to compare if two names point to the same "object, you can
use the "is" operator.

a is b
c is a

etc.

>
>>> A pointer = a variable that has as a value a memory address a variable =
>>> a memory address that has as a value the actual value we want to store.
>>
>>
>> These are really C terms, not Python terms. Stop thinking that C is
>> behaving like Python.
>
>
>
> I think it behaves the same way, but lets here from someone else too.

I understand the Greeks invented democracy and all that, but facts
aren't subject to it.

>
> Whats the difference of "interpreting " to "compiling" ?

If only it could be googled.... Alas, no one has ever written anything
about technology on the internet. Ironic that...

Michael

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Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 01:55 +0000
  Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-13 12:03 +1000
  Re: A certainl part of an if() structure never gets executed. Kushal Kumaran <kushal.kumaran+python@gmail.com> - 2013-06-13 10:05 +0530
  Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-13 14:39 +1000
  Re: A certainl part of an if() structure never gets executed. Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 08:36 +0300
  Re: A certainl part of an if() structure never gets executed. Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 10:11 +0300
    Re: A certainl part of an if() structure never gets executed. Sibylle Koczian <nulla.epistola@web.de> - 2013-06-13 14:22 +0200
      Re: A certainl part of an if() structure never gets executed. Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 17:26 +0300
        Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-14 01:14 +0000
          Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 11:03 +0300
            Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-14 18:23 +1000
            Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-14 09:24 +0100
            Re: A certainl part of an if() structure never gets executed. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-14 11:28 +0300
              Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 11:41 +0300
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-14 18:50 +1000
                Re: A certainl part of an if() structure never gets executed. Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 10:03 +0100
                Re: A certainl part of an if() structure never gets executed. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-14 12:21 +0300
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 12:44 +0300
                Re: A certainl part of an if() structure never gets executed. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-14 15:40 +0300
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 16:07 +0300
                Re: A certainl part of an if() structure never gets executed. Zero Piraeus <schesis@gmail.com> - 2013-06-14 09:48 -0400
                Re: A certainl part of an if() structure never gets executed. rusi <rustompmody@gmail.com> - 2013-06-14 07:05 -0700
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 17:08 +0300
                Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-14 16:31 +0000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 19:56 +0300
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-15 03:18 +1000
                Re: A certainl part of an if() structure never gets executed. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-14 21:17 +0300
                Re: A certainl part of an if() structure never gets executed. Larry Hudson <orgnut@yahoo.com> - 2013-06-14 22:27 -0700
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-15 11:39 +0300
                Re: A certainl part of an if() structure never gets executed. Lele Gaifax <lele@metapensiero.it> - 2013-06-15 11:54 +0200
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-15 16:07 +0300
                Re: A certainl part of an if() structure never gets executed. Michael Torrie <torriem@gmail.com> - 2013-06-15 09:53 -0600
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-15 19:18 +0300
                Re: A certainl part of an if() structure never gets executed. Michael Torrie <torriem@gmail.com> - 2013-06-15 11:45 -0600
                Re: A certainl part of an if() structure never gets executed. Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-16 06:32 +0000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-16 11:07 +0300
                Re: A certainl part of an if() structure never gets executed. Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-16 09:22 +0000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-16 12:59 +0300
                Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-16 11:42 +0100
                Re: A certainl part of an if() structure never gets executed. Ferrous Cranus <support@superhost.gr> - 2013-06-16 14:06 +0300
                Re: A certainl part of an if() structure never gets executed. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-16 12:26 +0100
                Re: A certainl part of an if() structure never gets executed. YBM <ybmess@nooos.fr.invalid> - 2013-06-16 14:00 +0200
                Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-16 13:04 +0100
                Re: A certainl part of an if() structure never gets executed. Ferrous Cranus <support@superhost.gr> - 2013-06-16 16:38 +0300
                Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-16 19:50 +0100
                Re: A certainl part of an if() structure never gets executed. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-16 11:52 +0100
                Re: A certainl part of an if() structure never gets executed. Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-16 10:51 +0000
                Compiling vs interpreting [was Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-16 12:07 +0000
                Re: Compiling vs interpreting [was Re: A certainl part of an if() structure never gets executed.] Mark Janssen <dreamingforward@gmail.com> - 2013-06-16 12:31 -0700
                Re: Compiling vs interpreting [was Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-16 20:02 +0000
                Re: Compiling vs interpreting [was Re: A certainl part of an if() structure never gets executed.] Chris Angelico <rosuav@gmail.com> - 2013-06-17 08:26 +1000
                Re: Compiling vs interpreting [was Re: A certainl part of an if() structure never gets executed.] Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-16 23:13 -0400
                Re: A certainl part of an if() structure never gets executed. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-16 14:13 +0300
                Re: A certainl part of an if() structure never gets executed. Ferrous Cranus <support@superhost.gr> - 2013-06-16 16:47 +0300
                Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-16 19:53 +0100
                Re: A certainl part of an if() structure never gets executed. Νίκος <support@superhost.gr> - 2013-06-17 08:17 +0300
                Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-17 06:51 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Simpleton <support@superhost.gr> - 2013-06-17 14:34 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Michael Torrie <torriem@gmail.com> - 2013-06-17 05:58 -0600
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Simpleton <support@superhost.gr> - 2013-06-17 18:50 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Larry Hudson <orgnut@yahoo.com> - 2013-06-17 23:39 -0700
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 07:24 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Νίκος <support@superhost.gr> - 2013-06-18 11:49 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 09:05 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Νίκος <support@superhost.gr> - 2013-06-18 12:51 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Chris Angelico <rosuav@gmail.com> - 2013-06-18 20:22 +1000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Michael Torrie <torriem@gmail.com> - 2013-06-19 23:16 -0600
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-20 05:48 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Michael Torrie <torriem@gmail.com> - 2013-06-20 00:01 -0600
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] 88888 Dihedral <dihedral88888@gmail.com> - 2013-06-26 01:18 -0700
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Michael Torrie <torriem@gmail.com> - 2013-06-19 23:44 -0600
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Roel Schroeven <roel@roelschroeven.net> - 2013-06-20 19:19 +0200
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Terry Reedy <tjreedy@udel.edu> - 2013-06-17 10:22 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Simpleton <support@superhost.gr> - 2013-06-17 18:55 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-17 12:26 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-06-17 09:23 -0700
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Νίκος <support@superhost.gr> - 2013-06-17 20:17 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Terry Reedy <tjreedy@udel.edu> - 2013-06-17 18:16 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-17 23:09 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Νίκος <support@superhost.gr> - 2013-06-18 02:26 +0300
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 00:41 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Dave Angel <davea@davea.name> - 2013-06-17 21:06 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 02:42 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Dave Angel <davea@davea.name> - 2013-06-18 00:12 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 06:04 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 02:38 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-18 02:46 +0000
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-17 21:34 -0400
                Re: Variables versus name bindings [Re: A certainl part of an if() structure never gets executed.] Marcin Szamotulski <mszamot@gmail.com> - 2013-06-18 04:22 +0100
                Re: A certainl part of an if() structure never gets executed. Michael Weylandt <michael.weylandt@gmail.com> - 2013-06-17 07:56 +0100
                Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-16 12:50 +0000
                OT: C vs Python terminology (was: A certainl part of an if() structure never gets executed) Andreas Perstinger <andipersti@gmail.com> - 2013-06-16 13:22 +0200
                Re: OT: C vs Python terminology Dave Angel <davea@davea.name> - 2013-06-16 08:55 -0400
                Re: OT: C vs Python terminology Andreas Perstinger <andipersti@gmail.com> - 2013-06-16 17:02 +0200
                Re: OT: C vs Python terminology Dave Angel <davea@davea.name> - 2013-06-16 21:58 -0400
            Re: A certainl part of an if() structure never gets executed. "R. Michael Weylandt" <michael.weylandt@gmail.com> - 2013-06-14 09:28 +0100
            Re: A certainl part of an if() structure never gets executed. Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 09:35 +0100
            Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 11:44 +0300
              Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-14 18:57 +1000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 12:00 +0300
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-14 19:12 +1000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-14 12:47 +0300
                Re: A certainl part of an if() structure never gets executed. Tim Roberts <timr@probo.com> - 2013-06-15 18:55 -0700
                Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-16 05:09 +0000
                Re: A certainl part of an if() structure never gets executed. Nick the Gr33k <support@superhost.gr> - 2013-06-16 11:20 +0300
                Re: A certainl part of an if() structure never gets executed. Tim Roberts <timr@probo.com> - 2013-06-18 22:08 -0700
                Re: A certainl part of an if() structure never gets executed. Dave Angel <davea@davea.name> - 2013-06-19 01:42 -0400
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-19 17:14 +1000
                Re: A certainl part of an if() structure never gets executed. Νίκος <support@superhost.gr> - 2013-06-19 10:49 +0300
                Re: A certainl part of an if() structure never gets executed. Dave Angel <davea@davea.name> - 2013-06-19 04:06 -0400
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-19 18:21 +1000
                Re: A certainl part of an if() structure never gets executed. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-19 08:55 +0000
                Re: A certainl part of an if() structure never gets executed. Chris Angelico <rosuav@gmail.com> - 2013-06-19 19:14 +1000
                Re: A certainl part of an if() structure never gets executed. Grant Edwards <invalid@invalid.invalid> - 2013-06-14 14:38 +0000
              Re: A certainl part of an if() structure never gets executed. Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 10:05 +0100

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