Hi All, I think i'm failing to undersatnd how aggregate() is supposed to work.
example: test1<-sample(c(0,1),100,replace=T) test2<-sample(letters,100,replace=T) aggregate(test1,list(test2),sum) Error in data.frame(w, lapply(y, unlist, use.names = FALSE)) : arguments imply differing number of rows: 26, 0 I thought this would give me a list containing the number of ones that "belong" to each letter. What am I doing wrong? Thanks in advance, Gustaf -- email:[EMAIL PROTECTED] tel: +46(0)703051451 address: Kantorsgatan 50:190 75424 Uppsala Sweden ______________________________________________ R-help@stat.math.ethz.ch 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.