search for: sel_po

Dear All, I am experiencing some problems in resetting the values of some selected elements in a dataframe. Consider d<-seq(-1,1,length=16) dim(d)<-c(4,4) d<-as.data.frame(d) sel_pos<-which(d>0, arr.ind=TRUE) d[sel_pos]<- -9 which returns the error Error in `[<-.data.frame`(`*tmp*`, sel_pos, value = -9) : only logical matrix subscripts are allowed in replacement which is obscure to me. I am correctly selecting the positive elements in a data.frame and I'...