[R] How to get the duplicated elements from a vector?

Dimitris Rizopoulos d.rizopoulos at erasmusmc.nl
Wed Oct 29 15:00:38 CET 2008

check duplicated(), e.g.,

x <- c("yes", "no", "yes", "yes", "no", "not sure")

I hope it helps.


Leon Yee wrote:
> Dear all,
>     How can I get the duplicated elements from a vector? For example,
> x <- c("yes", "no", "yes", "yes", "no", "not sure"), how can I filter 
> out all the elements which occured >=2 times?
>     Thanks for any help!
> Regards,
> Leon
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Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus Medical Center

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