How to get standard deviation of rows in a matrix

On Wed, 9 Mar 2005 13:49:44 -0600, "Jagarlamudi, Choudary"
<choudary.jagar at swosu.edu> wrote :

Hi all,

  I am trying to find sd of my rows in a matrix and i get column sd inspite of extracting rows.
I tried to do the sqrt(var(x)) but that did'nt work as well,

Here is my data

genes
15 24 63 40
25 42 46 35
23 53 37 45
30 37 50 55
40 51 30 48

x<-sd(genes[1:5,])

This doesn't extract the rows, it just returns the same matrix.  As
the man page for sd says, when applied to a matrix it calculates the
standard deviation of each column.

What you want to do is to use the apply function.  Rows are the first
dimension, so you would use

apply(genes, 1, sd)

Duncan Murdoch