Dear Listmembers, I'm trying to fill up a dataframe depending on an arbitrary list of references:
Here is my code, which works: dat <- data.frame(c(60001,60001,60050,60050,60050),c(27,129,618,27,1579)) LR <- sort(unique(dat[,1])) LC <- sort(unique(dat[,2])) m <- as.data.frame(matrix(data=NA, nrow=length(LR), ncol=length(LC), dimnames=list(LR,LC))) for(i in 1:nrow(dat)){ m[as.character(dat[i,1]), as.character(dat[i,2])] <- 1 } m[is.na(m)] <- 0 Now I'm trying to prevent the loop, because it take ages for a list of 20000 entries, but I run out of ideas. Should I inflate my list beforehand and how? Can I adress the dataframe fields more effieciently? Thanks for your help. -- Dr. Florian Jansen Geobotany & Nature Conservation Institute of Botany and Landscape Ecology Ernst-Moritz-Arndt-University Grimmer Str. 88 17487 Greifswald Germany +49 (0)3834 86 4147 ______________________________________________ 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.