[R] Last element of a vector by group

[R. Michael Weylandt]

? duplicated

!duplicated(a.ord, fromLast = TRUE)


HTH,
Michael

On Tue, May 15, 2012 at 9:37 PM, Axel Urbiz <axel.urbiz at 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 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
>
> Axel.
>
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