Hi Christofer,

Check ?tapply, ?aggregate and ?ave.  Here is a way of doing in using the
first function:

tapply(Dat1[, 3], list(Dat1[,1], Dat1[,2]), sum, na.rm = TRUE)

HTH,
Jorge.-


On Wed, Dec 19, 2012 at 1:36 AM, Christofer Bogaso <> wrote:

> Dat1 <- structure(list(factor.sample.LETTERS.1.3...6..replace...T.. =
> structure(c(1L,
> 3L, 2L, 1L, 3L, 3L), .Label = c("A", "B", "C"), class = "factor"),
>     factor.sample.letters.1.2...6..replace...T.. = structure(c(2L,
>     2L, 1L, 1L, 2L, 1L), .Label = c("a", "b"), class = "factor"),
>     X1.6 = 1:6), .Names = c("factor.sample.LETTERS.1.3...6..replace...T..",
> "factor.sample.letters.1.2...6..replace...T..", "X1.6"), row.names = c(NA,
> -6L), class = "data.frame")
>

	[[alternative HTML version deleted]]


