[R] Remove Column from matrix

[arun]

Hi,

In this particular example, you may not be able to remove any columns:
because:
namVar <- 
c("TrlgWSST","TrlgWSSE","TrlgWSSR","SSdiff","TrlgWMSE","TrlgWR2","TrlgWR2adj","TrlgSSE","TrlgMSE","TrlgR2","TrlgR2adj","TrSSE","TrMSE","TrR2","TrR2adj","rdf2", 
"TelgSSE","TelgMSE","TelgR2","TelgR2adj","TelgWSSE","TelgWMSE" 
,"TelgWR2","TelgWR2adj","TeSSE","TeMSE","TeR2","TeR2adj","edf2","Runtime") Asse <- matrix(0,nrow=5,ncol=length(namVar), dimnames = list(NULL, namVar)) #JoAnn's suggestion
Asse[,1:3]<-2 
Asse[2,4] <-2000 
Asse[,5:10]<-3 
Asse[,11:20]<-5 
Asse[,21:30]<-12 
Asse[,1:5]
#     TrlgWSST TrlgWSSE TrlgWSSR SSdiff TrlgWMSE
#[1,]        2        2        2      0        3
#[2,]        2        2        2   2000        3
#[3,]        2        2        2      0        3
#[4,]        2        2        2      0        3
#[5,]        2        2        2      0        3

So, if you are not assigning :
#Asse[2,4] <-2000 
Then, Asse[,4] will be all zeros.

Asse[,!colSums(abs(Asse))==0] #will remove the columns which are all zeros
#or
Asse[,!apply(Asse,2,function(x) all(x==0))]
#will get the results you wanted.
A.K.



----- Original Message -----
From: frespider <frespider at hotmail.com>
To: r-help at r-project.org
Cc: 
Sent: Wednesday, November 21, 2012 12:52 PM
Subject: [R] Remove Column from matrix

Hi,,
Can I get help with this. I need to remove a column form the matrix if that
specific column has his all entry zero, here the code I wrote but it is not
working can you help me please

namVar <-
c("TrlgWSST","TrlgWSSE","TrlgWSSR","SSdiff","TrlgWMSE","TrlgWR2","TrlgWR2adj","TrlgSSE","TrlgMSE","TrlgR2","TrlgR2adj","TrSSE","TrMSE","TrR2","TrR2adj","rdf2",
"TelgSSE","TelgMSE","TelgR2","TelgR2adj","TelgWSSE","TelgWMSE"
,"TelgWR2","TelgWR2adj","TeSSE","TeMSE","TeR2","TeR2adj","edf2","Runtime")
Asse <- matrix(0,nrow=5,ncol=length(namVar))
Asse[,1:3]<-2
Asse[2,4] <-2000
Asse[,5:10]<-3
Asse[,11:20]<-5
Asse[,21:30]<-12
if(all(Asse[,"SSdiff"]==0)==TRUE){
Asse <- Asse[,-which(colnames(Asse)%in%"SSdiff")]}
            





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