# Re: [R] computing the average and standard deviation for many sets of triplicates, using "R-approach"

From: stephen sefick <ssefick_at_gmail.com>
Date: Wed, 18 Jun 2008 11:56:03 -0400

#is this what you want?
t <- matrix(rnorm(120), ncol=12)
(colnames(t) <- paste(rep(LETTERS[1:4], each=3), 1:3, sep=".")) f<-as.matrix(cbind(c(t[,1:3]), c(t[,4:6]), c(t[7:9]), c(t[10:12]))) colnames(f)<-paste(rep(LETTERS[1:4]))
library(prettyR)
describe(f, num.desc=c("mean", "sd"))

On Wed, Jun 18, 2008 at 10:17 AM, Daren Tan <daren76_at_hotmail.com> wrote:

>
> Below example has 4 sets of triplicates, without using for loop and
> iteratively cbind the columns, what is the "R-approach" of generating a
> matrix of 8 columns that are the averages and standard deviations ? The
> average and standard deviation columns should be side by side i.e. A.mean
> A.sd B.mean B.sd C.mean C.sd D.mean D.sd
>
> > t <- matrix(rnorm(120), ncol=12)> (colnames(t) <- paste(rep(LETTERS[1:4],
> each=3), 1:3, sep="."))  "A.1" "A.2" "A.3" "B.1" "B.2" "B.3" "C.1" "C.2"
> "C.3" "D.1" "D.2" "D.3"
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