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

• To: mathgroup at smc.vnet.net
• Subject: [mg29760] Re: [mg29758] Partitioning 1-D list into 2-D Matrix
• From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
• Date: Sun, 8 Jul 2001 01:00:06 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```One possibility:

In[2]:=
Flatten[Transpose[Partition[#,2]]&/@Partition[b,10],1]
Out[2]=
{{1,3,5,7,9},{2,4,6,8,10},{11,13,15,17,19},{12,14,16,18,20}}

--
Andrzej Kozlowski
Toyama International University
JAPAN

http://platon.c.u-tokyo.ac.jp/andrzej/
http://sigma.tuins.ac.jp/~andrzej/

on 01.7.7 3:26 PM, Krautschik, Chris G at krautschikc at intel.co.jp wrote:

> 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[].
>
> I could use brute force and select the elements as follows:
> <<...OLE_Obj...>>
> <<...OLE_Obj...>>
>
> I have a feeling there is a much better way to do this.
>