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Re: A bug in Partition?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg117431] Re: A bug in Partition?
  • From: Ray Koopman <koopman at sfu.ca>
  • Date: Fri, 18 Mar 2011 06:01:02 -0500 (EST)
  • References: <ilsri1$t4b$1@smc.vnet.net>

On Mar 17, 4:33 am, "Alexey Popkov" <lehi... at gmail.com> wrote:
> My second question is: is there universal way to pad partitioning list at
> the start without dropping any elements? I mean the same way as in the case
> of padding at the end. The solution I currently use is just a workaround:
>
> list = {a, b, c, d, e, f, g, i};
> Reverse /@ Reverse@Partition[Reverse@list, 3, 3, 1, x]
>
> Alexey

Use k = -Mod[Length@list, n, 1]

Partition[Range@7, 3,3, -1, 0]
Partition[Range@8, 3,3, -2, 0]
Partition[Range@9, 3,3, -3, 0]

{{0,0,1},{2,3,4},{5,6,7}}
{{0,1,2},{3,4,5},{6,7,8}}
{{1,2,3},{4,5,6},{7,8,9}}


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