Re: Calculating Averages for several

["Richard M. Heiberger" <rmh@temple.edu>]

## download abind from statlib

tmp <- data.frame(A=letters[c(1,1,1,1,1,2,2,2,2)],
                  B=letters[c(5,5,6,5,7,7,5,6,7)],
                  D=letters[c(3,3,3,4,4,3,4,4,4)],
                  E=rnorm(9),
                  F=rnorm(9))
tmp
tmp3 <- lapply(tmp[,4:5], function(x) tapply(x, tmp[,1:3], mean))
do.call("abind", c(tmp3, along=3.1))