Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2001
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Partitioning 1-D list into 2-D Matrix

  • To: mathgroup at smc.vnet.net
  • Subject: [mg29764] Re: [mg29758] Partitioning 1-D list into 2-D Matrix
  • From: BobHanlon at aol.com
  • Date: Sun, 8 Jul 2001 01:00:08 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

In a message dated 2001/7/7 3:09:27 AM, krautschikc at intel.co.jp writes:

>I have a question of how to best select elements from a list and reformat
>the list into a 2D matrix. Here is an example:
>
>b=Range[1,20]
>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}
>
>I would like to arrange the list into a 2D array of the following form:
>{{1, 3, 5, 7, 9}, {2, 4, 6, 8, 10}, {11, 13, 15, 17, 19}, {12, 14, 16,
>18,
>20}}
>
>Then
>bb=Partition[Partition[b,2],5] 
> <<...OLE_Obj...>> 
>almost does what I want if you view this array in MatrixForm[]. However,
>I
>would have to somehow get rid of the innner brackets. I am not sure how
>to
>do that with Flatten[].
>

b = Range[1, 20];

bb = Flatten[
  Transpose[Partition[#, 5]& /@ 
      Transpose[Partition[b, 2]]], 
  1]

{{1, 3, 5, 7, 9}, {2, 4, 6, 8, 10}, 
  {11, 13, 15, 17, 19}, 
  {12, 14, 16, 18, 20}}


Bob Hanlon
Chantilly, VA  USA


  • Prev by Date: TeXSave, TeXForm, etc.
  • Next by Date: Re: a couple of gripes
  • Previous by thread: Partitioning 1-D list into 2-D Matrix
  • Next by thread: Re: Partitioning 1-D list into 2-D Matrix