Groups > comp.soft-sys.math.mathematica > #3164

Re: Partition a list based on columns

From	DrMajorBob <btreat1@austin.rr.com>
Newsgroups	comp.soft-sys.math.mathematica
Subject	Re: Partition a list based on columns
Date	2011-06-17 09:52 +0000
Organization	Steven M. Christensen and Associates, Inc and MathTensor, Inc.
Message-ID	<itf859$239$1@smc.vnet.net> (permalink)
References	<itcdai$d13$1@smc.vnet.net> <201106170406.AAA28684@smc.vnet.net>

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How about

Clear[m, n]
m[x_List] := Module[{n = Sqrt@Length@x},
   Normal@SparseArray[
      Rule @@@
       Transpose@{SortBy[Flatten[Array[List, {n, n}], 1], Total], x}] /;
     IntegerQ@n
   ]
m[Range@9] // MatrixForm

(* suppressed *)

m[Range@16] // MatrixForm

(* suppressed *)

m[Range@7]

m[{1, 2, 3, 4, 5, 6, 7}]

Bobby

On Thu, 16 Jun 2011 23:06:31 -0500, Ray Koopman <koopman@sfu.ca> wrote:

> On Jun 16, 1:02 am, StatsMath <stats.ma...@gmail.com> wrote:
>> [...]
>>
>> What would be a good way to line up elements in a list in a diagonal
>> fashion, for ex: from Range[9] want to create the follwing matrix:
>>
>> 1 2 4
>> 3 5 7
>> 6 8 9
>
> This is better than my previous suggestion:
>
> m[n_] := Partition[FoldList[Plus,0,Join[Range[n-1],Range[n-1,1,-1]]],
>                    n, 1] + Range[n]
>


-- 
DrMajorBob@yahoo.com

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Thread

Partition a list based on columns StatsMath <stats.math8@gmail.com> - 2011-06-16 08:02 +0000
  Re: Partition a list based on columns Ray Koopman <koopman@sfu.ca> - 2011-06-16 10:24 +0000
  Re: Partition a list based on columns Ray Koopman <koopman@sfu.ca> - 2011-06-17 04:09 +0000
  Re: Partition a list based on columns Ray Koopman <koopman@sfu.ca> - 2011-06-17 04:06 +0000
  Re: Partition a list based on columns DrMajorBob <btreat1@austin.rr.com> - 2011-06-17 09:52 +0000

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