[R] sort matrix by sum of columns

[Dimitris Rizopoulos]

probably you're looking for ?order(), e.g.,

barplot(a[, order(colSums(a))], horiz = TRUE, legend.text = TRUE)


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
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Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Albert Vilella" <avilella at gmail.com>
To: "r help" <r-help at stat.math.ethz.ch>
Sent: Wednesday, June 21, 2006 12:38 PM
Subject: [R] sort matrix by sum of columns


> Hi all,
>
> I would like to know how can I sort the cols of a matrix by the sum 
> of
> their elements.
>
>
> a <- matrix(as.integer(rnorm(25,4,2)),10,5)
> colnames(a) = c("alfa","bravo","charlie","delta","echo")
>
> I guess I should use colSums, and then rearrange the matrix somehow
> according to the result.
>
> My idea is to display a "sorted" barplot:
>
> barplot(a, horiz=TRUE, legend.text=T)
>
> Thanks in advance,
>
>    Albert.
>
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