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

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Date Sat, 1 Aug 2015 18:58:14 -0400
Subject Re: Most pythonic way of rotating a circular list to a canonical point
From Joel Goldstick <joel.goldstick@gmail.com>
Cc "python-list@python.org" <python-list@python.org>
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On Sat, Aug 1, 2015 at 6:51 PM, Lukas Barth <mail@tinloaf.de> wrote:
> On Saturday, August 1, 2015 at 11:37:48 PM UTC+2, Emile van Sebille wrote:
>> Well, it looks to me that I don't know what a 'canonical rotation' is --
>
> That's because it is not defined. ;)
>
> I need a way to rotate one of these lists in a way so that it will produce the same output every time, regardless of what the input rotation was.
>
> Example:
>
> [0,1,2,3,4] => [0,1,2,3,4]
> [2,3,4,0,1] => [0,1,2,3,4]
> [3,4,0,1,2] => [0,1,2,3,4]
> ...
>
> It doesn't have to be "[0,1,2,3,4]", it can just as well be [2,3,4,1,0], as long as it's always the same.
>
> Did that make it clearer?
>
> Thanks a lot,
>
> Lukas

I've been following along.  The early suggestion to double one list
and see if the second list is in the double list seems to prove they
are the same -- one is just rotated to a different starting point.  I
don't understand the term 'canonical' in this example, but what is it
that the solution given doesn't provide for you?

-- 
Joel Goldstick
http://joelgoldstick.com

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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

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