This seems to work fine (notice the missing 'c(...)'; why did you think you needed it);
> with(datas, aggregate(list(r = r), by = list(id = id, mod1 = mod1),mean)) id mod1 r 1 1 1 0.980 2 4 1 0.640 3 7 1 0.490 4 10 1 0.180 5 1 2 0.295 6 5 2 0.490 7 8 2 0.330 8 11 2 0.600 9 6 3 -0.040 10 9 3 0.580 11 12 3 0.210 > On Sat, Feb 20, 2010 at 6:54 PM, AC Del Re <de...@wisc.edu> wrote: > 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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? [[alternative HTML version deleted]] ______________________________________________ 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.
