Re: [R] combination of columns in a matrix

Hi, sapply(colnames(m)[-ncol(m)],function(i) {x1<-cbind(m[,i],m[,ncol(m)]); length(which(x1[,1]!=0 & x1[,2]!=0))}) #A B C #2 1 2 A.K. - Original Message - From: Hermann Norpois To: r-help Cc: Sent: Friday, June 14, 2013 3:51 PM Subject: [R] combination of columns in a

[R] combination of columns in a matrix

Hello, I have a matrix m and I want to know how often does 1 (or !0) simultanously appear in A and REF, B and REF, C and REF. So actually I wish to automate following expression: > length (which (m[,1]!=0&m[,4]!=0)) [1] 2 > length (which (m[,2]!=0&m[,4]!=0)) [1] 1 Thanks Hermann > m A B C