Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!newsfeed.xs4all.nl!newsfeed5.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path: <rosuav@gmail.com>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.044
X-Spam-Evidence: '*H*': 0.91; '*S*': 0.00; 'interpreter': 0.05; 'differently.': 0.07; 'python': 0.08; 'dict': 0.09; 'run.': 0.09; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'predictable': 0.16; 'received:209.85.213.174': 0.16; 'received :mail-yx0-f174.google.com': 0.16; 'language': 0.16; 'wrote:': 0.18; 'header:In-Reply-To:1': 0.22; 'feb': 0.22; 'structure': 0.26; 'code.': 0.26; 'function': 0.27; 'code,': 0.28; 'order.': 0.28; 'script': 0.28; 'message-id:@mail.gmail.com': 0.29; 'pm,': 0.29; 'hash': 0.30; 'varies': 0.30; 'nobody': 0.31; 'source': 0.32; 'that,': 0.32; "isn't": 0.33; 'fri,': 0.34; 'anything': 0.34; 'keys': 0.34; 'to:addr:python-list': 0.35; 'something': 0.35; 'created': 0.37; 'received:google.com': 0.37; 'another': 0.37; 'either': 0.37; 'received:209.85': 0.38; 'back.': 0.38; 'could': 0.38; 'think': 0.38; 'data': 0.38; 'received:209': 0.39; 'being': 0.40; 'put': 0.40; 'to:addr:python.org': 0.40; 'more': 0.61; 'your': 0.61; 'results': 0.64; 'ever': 0.64; 'series': 0.67; 'exact': 0.68; '100%': 0.82; 'different.': 0.84; 'nathan': 0.84; 'ubiquitous': 0.84; 'promised': 0.93
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=eFucGqbgsT5fbz1+DqUcBUaFbiBS0AGoUUXW8FCcHkE=; b=JUmdMCP5HhTwAa1znBYHRJbgfwI/fdMkvmzfMdh2ITAQJyNd1eOzs6/uS9SrCNgh+v H2rtLuhOcBYi7WWsiVCHEn/AB6oKTeuUt56/hm9Df4IE+HyIl21PpV/Y/eC0fb9dPoiB b3IqSkAngSoRWr4lgIGKJf10UvmnkRshUHEg0=
MIME-Version: 1.0
In-Reply-To: <CAOFbRmJN=XicYeUjN9+a800FqvRGigA4p_88mU=Pj1ZRtcgwfw@mail.gmail.com>
References: <4F332007.9080800@wisc.edu> <jgv9ps$35g$1@dough.gmane.org> <mailman.5558.1328759017.27778.python-list@python.org> <Xns9FF46B35EDFF9duncanbooth@127.0.0.1> <mailman.5588.1328798176.27778.python-list@python.org> <Xns9FF497406322duncanbooth@127.0.0.1> <CAOFbRmJLyNA=-oM3eyASVE0EzA6SrjguP7Lv1Vsj2qA4=qU-cw@mail.gmail.com> <mailman.5597.1328805384.27778.python-list@python.org> <4f3471e9$0$29986$c3e8da3$5496439d@news.astraweb.com> <CAOFbRmJN=XicYeUjN9+a800FqvRGigA4p_88mU=Pj1ZRtcgwfw@mail.gmail.com>
Date: Fri, 10 Feb 2012 21:08:04 +1100
Subject: Re: frozendict
From: Chris Angelico <rosuav@gmail.com>
To: python-list@python.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://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: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.5645.1328868491.27778.python-list@python.org>
Lines: 18
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1328868491 news.xs4all.nl 6943 [2001:888:2000:d::a6]:35811
X-Complaints-To: abuse@xs4all.nl
Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:20151

On Fri, Feb 10, 2012 at 1:30 PM, Nathan Rice
<nathan.alexander.rice@gmail.com> wrote:
> The only thing needed to avoid the hash collision is that your hash
> function is not not 100% predictable just by looking at the python
> source code. =A0I don't see why every dict would have to be created
> differently. =A0I would think having the most ubiquitous data structure
> in your language be more predictable would be a priority. =A0Oh well....

It's perfectly predictable. If you put a series of keys into it, you
get those same keys back. Nobody ever promised anything about order.

If your hash function is not 100% predictable, that means it varies on
the basis of something that isn't part of either the Python
interpreter or the script being run. That means that, from one
execution to another of the exact same code, the results could be
different. The keys will come out in different orders.

ChrisA