Hi All, I am interested in aggregating a data frame based on 2 categories--mean effect size (r) for each 'id's' 'mod1'. The 'with' function works well when aggregating on one category (e.g., based on 'id' below) but doesnt work if I try 2 categories. How can this be accomplished?
# sample data id<-c(1,1,1,rep(4:12)) n<-c(10,20,13,22,28,12,12,36,19,12, 15,8) r<-c(.98,.56,.03,.64,.49,-.04,.49,.33,.58,.18, .6,.21) mod1<-factor(c(1,2,2, rep(c(1,2,3),3))) mod2<-c(1,2,15,rep(3,9)) datas<-data.frame(id,n,r,mod1,mod2) # one category works perfect: with(datas, aggregate(list(r = r), by = list(id = id),mean)) id r 1 1 0.5233333 2 4 0.6400000 3 5 0.4900000 4 6 -0.0400000 5 7 0.4900000 6 8 0.3300000 7 9 0.5800000 8 10 0.1800000 9 11 0.6000000 10 12 0.2100000 # trying with 2 categories: with(datas, aggregate(list(r = r), by = list(c(id = id, mod1 = mod1)),mean)) Error in FUN(X[[1L]], ...) : arguments must have same length Thank you, AC ______________________________________________ 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.
