# RE: [R] R matrix sorting question

From: Tuszynski, Jaroslaw W. <JAROSLAW.W.TUSZYNSKI_at_saic.com>
Date: Fri 20 May 2005 - 04:30:05 EST

Try:

> A=matrix(c(1,3,4,5,7, -0.2, 0.8, 0.3, 0.2, 0.9 ),5,2) > A

[,1] [,2]
[1,] 1 -0.2
[2,] 3 0.8
[3,] 4 0.3
[4,] 5 0.2
[5,] 7 0.9
> A[order(A[,2]), ]

[,1] [,2]
[1,] 1 -0.2
[2,] 5 0.2
[3,] 4 0.3
[4,] 3 0.8
[5,] 7 0.9

Jarek

```====================================================\=======

Jarek Tuszynski, PhD.                           o / \
Science Applications International Corporation  <\__,|
(703) 676-4192                                   ">   \
Jaroslaw.W.Tuszynski@saic.com                     `    \

```

-----Original Message-----
From: r-help-bounces@stat.math.ethz.ch
[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of
insu_paek@harcourt.com
Sent: Thursday, May 19, 2005 1:43 PM
To: R-help@stat.math.ethz.ch
Subject: [R] R matrix sorting question

Dear there,

I am trying to do the following stuff. Could you let me know how to do it efficiently?

> aaa
[,1] [,2]
[1,] 1 -0.2
[2,] 3 0.8
[3,] 4 0.3
[4,] 5 0.2
[5,] 7 0.9

And I would like to sort the matrix by column 2 (and accordingly column 1 sorted as well).
The desired matrix will be

```1  -0.2
5   0.2
4   0.3
3   0.8
7   0.9

```

If using Excel or SAS, I can do this easily, but I couldn't figure out how to do it in R.
Could you let me know the efficient way to do this ?  I appreciate if the solution or reply comes as quickly as possible.

Thank you very much.

Insu

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