Gator Connection wrote: > I am a beginner and this is a naive question. > I have the following data set. > row column height > 1 2 96 > 3 7 67 > 9 25 77 > ...... > I have a matrix of 50*100 data points and about 60% of them are zeros. > I want to put the height data into the matrix according to their row and > column numbers. does anybody have experience in setting up such matrix? > Your help is highly appreciated. > Jack Hi Jack, Well, what do you know? I thought that this:
x<-matrix(c(rep(1:5,each=3),rep(1:3,5),sample(10:100,15)),ncol=3) x newmat<-matrix(0,nrow=5,ncol=3) newmat[x[,1],x[,2]]<-x[,3] would do it, but it doesn't. However, # scramble the matrix x1<-x[sample(1:15,15),] # create a new matrix by ordering it by row and column newmat<-matrix(x1[order(x1[,1],x1[,2]),3],ncol=3,byrow=TRUE) newmat works for me Jim ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
