I am not sure what you mean by eliminating a row. Now if you want only one copy of each 'id', and it is the first one, the you can use 'duplicated':
> x <- with(datas, aggregate(list(r = r), by = list(id = id, mod1 = mod1),mean)) > x 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 > subset(x, !duplicated(id)) id mod1 r 1 1 1 0.98 2 4 1 0.64 3 7 1 0.49 4 10 1 0.18 6 5 2 0.49 7 8 2 0.33 8 11 2 0.60 9 6 3 -0.04 10 9 3 0.58 11 12 3 0.21 On Sat, Feb 20, 2010 at 8:07 PM, AC Del Re <de...@wisc.edu> wrote: > Perfect! Thanks Jim. > > Do you know how I could then reduce the data even further? > Specifically, reducing it to 1 id per row? In this dataset, id 1 would > have one row eliminated. > Assume the data is much larger and cannot be deleted by visual > inspection and elimination one row at a time. > > > Thank you, > > AC > > On Sat, Feb 20, 2010 at 6:26 PM, jim holtman <jholt...@gmail.com> wrote: > > 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? > > > -- 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.
