Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #94870

Re: Most pythonic way of rotating a circular list to a canonical point

Path csiph.com!usenet.pasdenom.info!news.redatomik.org!newsfeed.xs4all.nl!newsfeed8.news.xs4all.nl!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <cameron@cskk.homeip.net>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.029
X-Spam-Evidence '*H*': 0.94; '*S*': 0.00; 'smallest': 0.07; 'suggest': 0.15; 'computes': 0.16; 'from:addr:cs': 0.16; 'from:addr:zip.com.au': 0.16; 'from:name:cameron simpson': 0.16; 'lukas': 0.16; 'message-id:@cskk.homeip.net': 0.16; 'rotation': 0.16; 'simpson': 0.16; 'wrote:': 0.16; 'element': 0.18; 'do.': 0.22; 'aspect': 0.22; 'cheers,': 0.22; 'needed.': 0.23; 'second': 0.24; 'header:In-Reply-To:1': 0.24; 'header:User-Agent:1': 0.26; "doesn't": 0.26; 'subject:list': 0.26; 'compare': 0.27; 'start,': 0.27; 'idea': 0.28; 'fine': 0.28; 'comparison': 0.29; 'point': 0.33; 'clarify': 0.33; 'list': 0.34; 'but': 0.36; 'should': 0.36; 'instead': 0.36; 'there': 0.36; 'to:addr:python-list': 0.36; 'subject:: ': 0.37; 'charset:us-ascii': 0.37; 'starting': 0.37; 'does': 0.39; 'enough': 0.39; 'easily': 0.39; 'to:addr:python.org': 0.40; 'matter': 0.63; 'is.': 0.63; 'more': 0.63; 'cameron': 0.66; 'equals': 0.66; 'received:61': 0.72; 'walk': 0.72; 'eliminates': 0.93
X-Authentication-Info Submitted using ID cskk@bigpond.com
X-Authority-Analysis v=2.0 cv=EJGEIilC c=1 sm=1 a=Xl+DAPPvrAuutrzkOAYnNw==:17 a=vrnE16BAAAAA:8 a=ZtCCktOnAAAA:8 a=yEdEr6MRgwAA:10 a=uRRa74qj2VoA:10 a=Q6FeT2ecvh0l6MGZrNIA:9 a=CjuIK1q_8ugA:10 a=Xl+DAPPvrAuutrzkOAYnNw==:117
Date Sun, 2 Aug 2015 08:25:30 +1000
From Cameron Simpson <cs@zip.com.au>
To python-list@python.org
Subject Re: Most pythonic way of rotating a circular list to a canonical point
MIME-Version 1.0
Content-Type text/plain; charset=us-ascii; format=flowed
Content-Disposition inline
In-Reply-To <e5b15806-88bb-4d57-95e6-e2f5e6cb5f44@googlegroups.com>
User-Agent Mutt/1.5.23 (2014-03-12)
References <e5b15806-88bb-4d57-95e6-e2f5e6cb5f44@googlegroups.com>
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.20+
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.1145.1438468309.3674.python-list@python.org> (permalink)
Lines 18
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1438468309 news.xs4all.nl 2843 [2001:888:2000:d::a6]:33492
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:94870

Show key headers only | View raw

On 01Aug2015 14:24, Lukas Barth <mail@tinloaf.de> wrote:
>Perhaps I should clarify a bit:
>- I definitely need a "canonical rotation" - just a comparison result is not enough

Fine. This also eliminates any solution which just computes a hash.

>- It does not matter what that rotation is. Starting with the smallest element was just an idea by me, any rotation that can easily produced will do.

That's a fine way to start, but more work than is needed.

Might I suggest instead simply starting with the leftmost element in the first 
list; call this elem0.  Then walk the second list from 0 to len(list2). If that 
element equals elem0, _then_ compare the list at that point as you suggested.

Is there an aspect of this which doesn't work?

Cheers,
Cameron Simpson <cs@zip.com.au>

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 13:34 -0700
  Re: Most pythonic way of rotating a circular list to a canonical point Emile van Sebille <emile@fenx.com> - 2015-08-01 13:49 -0700
    Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 14:12 -0700
      Re: Most pythonic way of rotating a circular list to a canonical point Emile van Sebille <emile@fenx.com> - 2015-08-01 14:29 -0700
  Re: Most pythonic way of rotating a circular list to a canonical point Marko Rauhamaa <marko@pacujo.net> - 2015-08-01 23:57 +0300
    Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 14:04 -0700
      Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 16:32 -0700
      Re: Most pythonic way of rotating a circular list to a canonical point Marko Rauhamaa <marko@pacujo.net> - 2015-08-02 09:25 +0300
  Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 14:24 -0700
    Re: Most pythonic way of rotating a circular list to a canonical point Emile van Sebille <emile@fenx.com> - 2015-08-01 14:36 -0700
      Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 15:51 -0700
        Re: Most pythonic way of rotating a circular list to a canonical point Joel Goldstick <joel.goldstick@gmail.com> - 2015-08-01 18:58 -0400
        Re: Most pythonic way of rotating a circular list to a canonical point Josh English <Joshua.R.English@gmail.com> - 2015-08-01 16:43 -0700
        Re: Most pythonic way of rotating a circular list to a canonical point Steven D'Aprano <steve@pearwood.info> - 2015-08-02 18:17 +1000
    Re: Most pythonic way of rotating a circular list to a canonical point Paul Rubin <no.email@nospam.invalid> - 2015-08-01 14:43 -0700
      Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 15:53 -0700
        Re: Most pythonic way of rotating a circular list to a canonical point Paul Rubin <no.email@nospam.invalid> - 2015-08-01 19:47 -0700
          Re: Most pythonic way of rotating a circular list to a canonical point Paul Rubin <no.email@nospam.invalid> - 2015-08-01 20:02 -0700
    Re: Most pythonic way of rotating a circular list to a canonical point Cameron Simpson <cs@zip.com.au> - 2015-08-02 08:25 +1000
      Re: Most pythonic way of rotating a circular list to a canonical point Lukas Barth <mail@tinloaf.de> - 2015-08-01 15:55 -0700
        Re: Most pythonic way of rotating a circular list to a canonical point Cameron Simpson <cs@zip.com.au> - 2015-08-02 11:20 +1000
  Re: Most pythonic way of rotating a circular list to a canonical point wolfram.hinderer@googlemail.com - 2015-08-01 17:07 -0700
  Re: Most pythonic way of rotating a circular list to a canonical point pavlovevidence@gmail.com - 2015-08-02 03:51 -0700
  Re: Most pythonic way of rotating a circular list to a canonical point Tim Chase <python.list@tim.thechases.com> - 2015-08-02 13:19 -0500
  Re: Most pythonic way of rotating a circular list to a canonical point Larry Hudson <orgnut@yahoo.com> - 2015-08-02 13:01 -0700
    Re: Most pythonic way of rotating a circular list to a canonical point Joonas Liik <liik.joonas@gmail.com> - 2015-08-02 23:58 +0300
      Re: Most pythonic way of rotating a circular list to a canonical point Larry Hudson <orgnut@yahoo.com> - 2015-08-03 12:56 -0700
    Re: Most pythonic way of rotating a circular list to a canonical point Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-08-03 15:19 +0100

csiph-web