[R] standardising a data matrix

[Paulo Justiniano Ribeiro Jr]

Hi Tord

What about apply:

apply(onorm, 2, function(x){(x - mean(x))/sqrt(var(x))})

Cheers
P.J.

On Fri, 2 Mar 2001,
Tord Snall wrote:

> Dear all,
> I would like to standardise my data. Here is an exemple for two columns:
> 
> > onorm<- read.table("onorm.txt", header=T)
> > names(onorm)
> [1] "on1" "on2" "on3" "on4" "on5"
> > norm<- data.frame((onorm$on1-mean(onorm$on1))/stdev(onorm$on1),
> (onorm$on2-mean(onorm$on2))/stdev(onorm$on2))
> 
> I would be happy however not having got to do this coulumnwise since I have
> about 80 columns. Could someone please give a hint on how to do this for
> the whole matrix. 
> 
> The names of the coulumns are on1, on2 etc. as above. I want the columns in
> the new standardised dataset to have the names son1, son2 etc, i.e. adding
> an s to all the original column names. How do I do that?
> 
> Thanks in advance!
> 
> Sincerely,
> Tord Snäll
> 
> -----------------------------------------------------------------------
> Tord Snäll
> Avd. f växtekologi, Evolutionsbiologiskt centrum, Uppsala universitet
> Dept. of Plant Ecology, Evolutionary Biology Centre, Uppsala University
> Villavägen 14			
> SE-752 36 Uppsala, Sweden
> Tel: 018-471 28 82 (int +46 18 471 28 82) (work)
> Tel: 018-25 71 33 (int +46 18 25 71 33) (home)
> Fax: 018-55 34 19 (int +46 18 55 34 19) (work)
> E-mail: Tord.Snall at ebc.uu.se
> http://www.vaxtbio.uu.se/resfold/tord_s.htm
> ------------------------------------------------------------------------
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Paulo Justiniano Ribeiro Jr
Dept Maths & Stats  -  Fylde College
Lancaster University
Lancaster LA1 4YF   -  U.K.

e-mail: paulojus at est.ufpr.br
http://www.maths.lancs.ac.uk/~ribeiro

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