[R] R matrix sorting question

Tuszynski, Jaroslaw W. JAROSLAW.W.TUSZYNSKI at saic.com
Thu May 19 20:30:05 CEST 2005


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 at saic.com                     `    \



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