It should be simple but i do not find the right keywords: Dup = c(1,2,3,4,1,2,3,5) I need 4,5 as result unique(Dup) gives me [1] 4 1 2 3 5 duplicated(Dup) gives me [1] FALSE FALSE FALSE FALSE TRUE TRUE TRUE FALSE I need [1] TRUE TRUE TRUE FALSE TRUE TRUE TRUE FALSE Kind regards Knut