[R] Problem with a Matrix

Dear All, I have a problem in making a matrix from a data. I did a summary data from a big data frame using (ddply), the resulting table is like that: Site.NoPlant.NameCover.Percentage 1XXX15 1YYY 20 2XXX

Re: [R] Problem with a Matrix

Hi Petr, Finally, I got the solution like you explained and I find another one like the following: Cover <- tapply(cover[,3], cover[, c(1,2)], c) It is working great. Thanks for your help, Hamada -- View this message in context: http://r.789695.n4.nabble.com/Problem-with-a-Matrix-tp4455954p44