If the factor have only level: apply(m1, 2, tapply, addNA(part2), mean)[-2,,drop = FALSE]
On Tue, Mar 16, 2010 at 12:43 PM, Christophe Genolini <cgeno...@u-paris10.fr> wrote: > As I told you in private, thanks, it works perfectly. > > More precisely, I am working with 3D array. Your code works well (both on > matrix or on array). > But when part is a factor with only one value, the result has not a correct > dimension (vector if m is a matrix, a matrix if m is an array). > Any way to fix that ? > > m1 <- matrix(1:12,4) > m2 <- array(1:24,dim=c(4,3,2)) > part1 <- factor(c("A","B","A","B"),levels=c("A","B","C")) > part2 <- factor(c("A","A","A","A"),levels=c("A")) > > apply(m1, 2, tapply, part1, mean) ##Perfect (dim=c(3,3)) > apply(m1, 2, tapply, part2, mean) ## dim=NULL... > > apply(m2, c(2,3), tapply, part1, mean) ## Perfect (dim=c(3,3,2)) > apply(m2, c(2,3), tapply, part2, mean) ## dim=c(3,2) > > > Christophe > > Try this: > > apply(m, 2, tapply, part, mean) > > On Mon, Mar 15, 2010 at 2:10 PM, Christophe Genolini > <cgeno...@u-paris10.fr> wrote: > > > 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 > > ______________________________________________ > 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. > > > > > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O ______________________________________________ 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.