# [R] unique vs duplicate problem

jim holtman jholtman at gmail.com
Mon Jul 9 18:47:42 CEST 2012

```Here is one way of doing it -- you can create your own functions:

>  x <- c(1, 2, 3, 3)
>
> allDup <-
+ function (value)
+ {
+     duplicated(value) | duplicated(value, fromLast = TRUE)
+ }
>
> duped <- unique(x[allDup(x)])
> duped
[1] 3
>
> setdiff(unique(x), duped)
[1] 1 2
>
>

On Mon, Jul 9, 2012 at 12:42 PM, Nico902 <descostes at ciml.univ-mrs.fr> wrote:
> Hi,
>
> Let say I have a numeric vector:   x <- c(1, 2, 3, 3).
>
> I want on one hand numbers which are not duplicated ie "1,2" and duplicated
> "3".
>
> so I did:
>
>>duplicated(x)
> FALSE FALSE FALSE TRUE
>> unique(x)
> 1 2 3
>
> which is not what I want. Is there a function in R to have the following
> result:
>
>>duplicated(x)
> FALSE FALSE TRUE TRUE
>>unique(x)
> 1 2
>
> I could do it by programming some loops but I reckon somebody programmed a
>
> Cheers.
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/unique-vs-duplicate-problem-tp4635868.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> and provide commented, minimal, self-contained, reproducible code.

--
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

```