[R] Variance Calculation in R

[Henrique Dallazuanna]

Then you can try:

rownames(data.matrix) <- as.character(data.matrix$ProbeID)
data.matrix <- data.matrix[-1]

as.matrix(apply(data.matrix1, 1, var))

or

out <- apply(data.matrix1, 1, var)
data.frame(ProbeID = names(out), Variance = unname(out))

Works for me


On 02/03/2008, Keizer_71 <christophe.lo at gmail.com> wrote:
>
> Hi Henrique,
>
> It is definitely better, but it doesn't show me the ProbeID which identify
> the probes name
>
> Here was the result when i export to excel with your code.
>
>  "Variance"	
> 1 2.425509867 21.6216446425273	
>
>
> any suggestions?
>
> thanks,
> Kei
>
>
> Keizer_71 wrote:
> >
> > Hello,
> >
> > Thanks everyone for helping me with the previous queries.
> >
> > step 1: Here is the orginal data: short sample
> >
> > 	ProbeID	    Sample_1_D	Sample_1_C    Sample_2_D	   Sample_2_C
> > 1	224588_at   2.425509867	11.34031409   11.46868531	   11.75741478
> >
> > step 2: i calculate the variance of the sample using this R code
> >
> > x<-1:20000
> > y<-2:141
> > data.matrix<-data.matrix(data[,y])#create data.matrix
> > variableprobe<-apply(data.matrix[x,],1,var)
> >
> > step 3: however, when i type in variableprobe, it gives me this.
> >
> > 1	21.58257457
> >
> > step 4: I need the code to output this:
> >
> > 	ProbeID	    Variance	
> > 1	224588_at   21.58257457
> >
> >
> > What do i need to do to modify the code to give me better description like
> > the one above?
> >
> > thank.
> > Keizer
> > 	
> >
> >
> >
>
> --
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>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O