R help - Dec 2011 - Output table from for loop

Hi, this might be basic but can't get it to work and it is hampering my R
usage:

#the loop is checking variance of rows, and cutting out rows with
var>numVec[i]
#I define outMat as object names I want to output to (does this make sense?
how else
#can I define sequential numbered output?)
#numVec is numbers I use in the loop

head(Counts)

             AN1  AN2   AN3   AN4   var
GENE1      99     0     6      0      2360
GENE2    183   136   137    160   496
GENE3    301   199   233    187   1856

outMat<-paste("NewCounts", 1:5, sep="_") #names of 
numVec<-c(100,200,500,1000,1500)
cutGenes<-function(x) {
	for (i in 1:5) {
		keep<- Counts$var<numVec[i] #gives logical vector
		keep<-Counts[keep=="TRUE",] #apply logical vector to count data
(table)
		outMat[i]<-keep
}
}

#this all works fine if I define 'outMat[i]' as 'outMat' but
then I can't
use the loop! The loop seems to make #outMat[i] take the i element of
'keep'
and only stores this. 

#Help much appreciated, sorry if it is VERY basic, just a head scratcher for
me.

Thanks,

Bruce.

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I'd do it like this:

nums = 10:30

OutList <- vector("list", length(nums)) # The key is that you need
to
return in a list: your loop iterations were all operating on the same
object OutMat and accessing different elements thereof instead of
creating new objects

for(cn in seq_along(nums)) OutList[[i]] <- Counts[Counts$var < nums[cn], ]

Michael

On Wed, Dec 7, 2011 at 10:39 AM, bmoran <bruce.moran at teagasc.ie>
wrote:
> Hi, this might be basic but can't get it to work and it is hampering my
R
> usage:
>
> #the loop is checking variance of rows, and cutting out rows with
> var>numVec[i]
> #I define outMat as object names I want to output to (does this make sense?
> how else
> #can I define sequential numbered output?)
> #numVec is numbers I use in the loop
>
> head(Counts)
>
> ? ? ? ? ? ? AN1 ?AN2 ? AN3 ? AN4 ? var
> GENE1 ? ? ?99 ? ? 0 ? ? 6 ? ? ?0 ? ? ?2360
> GENE2 ? ?183 ? 136 ? 137 ? ?160 ? 496
> GENE3 ? ?301 ? 199 ? 233 ? ?187 ? 1856
>
> outMat<-paste("NewCounts", 1:5, sep="_") #names of
> numVec<-c(100,200,500,1000,1500)
> cutGenes<-function(x) {
> ? ? ? ?for (i in 1:5) {
> ? ? ? ? ? ? ? ?keep<- Counts$var<numVec[i] #gives logical vector
> ? ? ? ? ? ? ? ?keep<-Counts[keep=="TRUE",] #apply logical
vector to count data (table)
> ? ? ? ? ? ? ? ?outMat[i]<-keep
> }
> }
>
> #this all works fine if I define 'outMat[i]' as 'outMat'
but then I can't
> use the loop! The loop seems to make #outMat[i] take the i element of
'keep'
> and only stores this.
>
> #Help much appreciated, sorry if it is VERY basic, just a head scratcher
for
> me.
>
> Thanks,
>
> Bruce.
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Output-table-from-for-loop-tp4169386p4169386.html
> Sent from the R help mailing list archive at Nabble.com.
>
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