[R] crosstabulation of means

[R. Heberto Ghezzo]

Hello, I am trying to print a crosttabulation of mean,sd,n for a
continuous variable crossclassified by anoother/s grouping variables. I
came up with:
xtab2 <- function(x,g1,g2) {
 funy <- function(z)
   list(mean(z,na.rm=T),sd(z,na.rm=T),length(z))
 aa <- by(x,list(g1,g2),funy)
 bb <- matrix(unlist(aa),nrow=3
   ,dimnames=list(c("mean","sd","n"),
                rep(levels(as.factor(g2)),
                rep(length(levels(as.factor(g1))),
                    length(levels(as.factor(g2)))) ) ))
}
but as you can see the labels of the columns correspond only to the
second factor, and if I try to generalize it to 3 grouping variables the
thing does not work.
Any suggestions please on how to write the dimnames paragraph
appropriately?
Thanks


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