Dear useRs, Given this code I end up with a list of class "by":
a <- sample(1:5,200,replace=TRUE) b <- sample(c("v1","v2","v3"),200,replace=TRUE) c <- sample(c(11,22,33),200,replace=TRUE) data <- runif(200) grouped <- by(data,list(a,b,c),function(x) {c(min=min(x),max=max(x), median=round(median(x),digits=2),mean=round(mean(x),digits=2))}) dfr <- do.call("rbind",grouped) #the levels are missing #---------- grouped typeof(grouped) class(grouped) dimnames(grouped) How do I get at the levels of the 'group by' variables for each subset? For example, from this part of the "by" list I want 4, v2 and 33: : 4 : v2 : 33 min max median mean 0.3897450 0.9215315 0.7300000 0.6700000 --------------------------------------- Thank you, b. ______________________________________________ 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