Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed2a.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path: <python-python-list@m.gmane.org>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.001
X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'subject:Python': 0.06; 'string': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'subject:into': 0.09; 'type,': 0.09; '\xe2\x80\x94': 0.09; 'python': 0.11; '*values*': 0.16; 'comparable.': 0.16; 'energies': 0.16; 'fine.': 0.16; 'finney': 0.16; 'identifiers.': 0.16; 'objects.': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'reliably': 0.16; 'subject:variable': 0.16; 'trying': 0.19; 'not,': 0.20; 'header :User-Agent:1': 0.23; 'comparing': 0.24; 'regardless': 0.24; 'compare': 0.26; 'values': 0.27; 'header:X-Complaints-To:1': 0.27; "doesn't": 0.30; "i'm": 0.30; 'getting': 0.31; 'commonly': 0.31; 'writes:': 0.31; 'languages': 0.32; 'everyone': 0.33; 'objects': 0.35; 'but': 0.35; 'there': 0.35; 'really': 0.36; 'received:com.au': 0.36; 'subject:?': 0.36; 'ben': 0.38; 'to:addr :python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'subject:Can': 0.60; 'no.': 0.61; 'such': 0.63; 'choose': 0.64; 'telling': 0.64; 'democracy': 0.84; 'received:125': 0.84
X-Injected-Via-Gmane: http://gmane.org/
To: python-list@python.org
From: Ben Finney <ben+python@benfinney.id.au>
Subject: Re: Can global variable be passed into Python function?
Date: Sun, 02 Mar 2014 00:03:32 +1100
References: <27ac2248-0ca3-4ba6-9d25-eaad324bc5e9@googlegroups.com> <bd36a46b-d704-4eb1-9b7d-1308d1fb6699@googlegroups.com> <mailman.7435.1393523704.18130.python-list@python.org> <5f4f5a5f-327a-4616-8235-17ee9e74c488@googlegroups.com> <530fef58$0$11113$c3e8da3@news.astraweb.com> <e24e0817-67d1-4dbd-b3ba-9250e735d261@googlegroups.com> <mailman.7453.1393562612.18130.python-list@python.org> <871tynznpd.fsf@elektro.pacujo.net> <53104798$0$11113$c3e8da3@news.astraweb.com> <mailman.7460.1393577227.18130.python-list@python.org> <87ha7jy2qs.fsf@elektro.pacujo.net> <mailman.7481.1393629442.18130.python-list@python.org> <87k3ceeq0m.fsf@elektro.pacujo.net> <mailman.7486.1393635051.18130.python-list@python.org> <87zjlad8q4.fsf@elektro.pacujo.net> <mailman.7492.1393638091.18130.python-list@python.org> <874n3irz04.fsf@elektro.pacujo.net> <mailman.7506.1393670936.18130.python-list@python.org> <87k3ceqhti.fsf@elektro.pacujo.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
X-Gmane-NNTP-Posting-Host: vmx15867.hosting24.com.au
X-Public-Key-ID: 0xBD41714B
X-Public-Key-Fingerprint: 9CFE 12B0 791A 4267 887F  520C B7AC 2E51 BD41 714B
X-Public-Key-URL: http://www.benfinney.id.au/contact/bfinney-gpg.asc
X-Post-From: Ben Finney <bignose+hates-spam@benfinney.id.au>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (gnu/linux)
Cancel-Lock: sha1:dnlSulSJRbjdx8jLVJHHRLtmZkg=
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list/>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.7512.1393679028.18130.python-list@python.org>
Lines: 39
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1393679028 news.xs4all.nl 2939 [2001:888:2000:d::a6]:33858
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:67314

Marko Rauhamaa <marko@pacujo.net> writes:

> Ben Finney <ben+python@benfinney.id.au>:
>
> > Use ‘==’, since that's all that matters for getting a value that will
> > work fine.
>
> You are telling me to use '==' if I choose string objects and 'is' if I
> choose some other objects.

No. I'm telling you that ‘is’ is *wrong* for comparing strings, because
it is unreliable.

> I prefer a solution that works regardless of what objects I choose for
> identifiers.

Some languages have a “symbol” type, whose values can be directly
compared. Python doesn't have such a type. If you want to use strings as
a substitute, go ahead: they work fine.

But compare strings by *equality*, not identity, because it's their
*values* which will be the identifiers. Their object identity will not
be reliably comparable.

That's what everyone has been telling you all along, for reasons already
explained.

> There really is no taboo against string object identity if you know what
> you are doing.

You, as has been amply demonstrated, do not, despite your dogmatic
assertions.

-- 
 \     “Under democracy one party always devotes its chief energies to |
  `\       trying to prove that the other party is unfit to rule — and |
_o__)         both commonly succeed, and are right.” —Henry L. Mencken |
Ben Finney