Hi the list,As it is say in its doc, the aggregate function remove empty subsets. Is it possible to NOT remove empty subset ?
--- 8< -------
m <- matrix(1:12,4)
part <- factor(c("A","B","A","B"),levels=c("A","B","C"))
aggregate(m,list(part),mean)### I get: # Group.1 V1 V2 V3 # 1 A 2 6 10 # 2 B 3 7 11 # ### I would like: # Group.1 V1 V2 V3 # 1 A 2 6 10 # 2 B 3 7 11 # 3 C NA NA NA --- 8< ------ Thanks Christophe ______________________________________________ [email protected] 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.

