[R] Last element of a vector by group

Dear List, How can I get a logical vector as shown by a.ord.last below (i.e., it is FALSE whenever there are subsequent equal values of an ordered vector and FALSE otherwise)? a - c(1,1,2,1,3,4,3,5,6) a.ord - a[order(a)] a.ord a.ord.last - c(F, F, T, T, F, T, T, T, T) Thanks for any help

Re: [R] Last element of a vector by group

? duplicated !duplicated(a.ord, fromLast = TRUE) HTH, Michael On Tue, May 15, 2012 at 9:37 PM, Axel Urbiz axel.ur...@gmail.com wrote: Dear List, How can I get a logical vector as shown by a.ord.last below (i.e., it is FALSE whenever there are subsequent equal values of an ordered vector