[R] How to get duplicated items in a vector?

[Gabor Grothendieck]

Try this:

> x <- c(1, 2, 3, 3, 4, 5)

> ave(x, x, FUN = length) > 1
[1] FALSE FALSE  TRUE  TRUE FALSE FALSE


On Thu, Oct 1, 2009 at 10:42 PM, Peng Yu <pengyu.ut at gmail.com> wrote:
> Hi,
>
>> x=c(rep(1,3),rep(3,2))
>> x
> [1] 1 1 1 3 3
>> duplicated(x)
> [1] FALSE  TRUE  TRUE FALSE  TRUE
>>
>
> As shown in the above code, 'duplicated' doesn't return 'F' for the
> first '1' and first '3' in 'x'. I am wondering if there is a function
> that can return an indicator for any element whether it appears in a
> vector twice or more.
>
> Regards,
> Peng
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>