I am trying to sort a list and the data is obiously not in the right format. I am trying: x <- list() x[["A"]] <- 1 x[["B"]] <- 2 order(x) But am getting: Error in order(x) : unimplemented type 'list' in 'orderVector1' How should I change the list so that it can be sorted? What kinds of objects (classes of objects) can be sorted? Thank you. Kevin