R help - Aug 2013 - Extracting only multiple occurrences

Hoping someone here can help me with this small problem.
set.seed(2013)

x<-sort(c(letters,letters[sample(26,10,1)]))

This gives a vector of 36 letters with some muliples (in this case,
g,m,s,t,u,v,x,y). Now what I need is to get rid of the ones that only occur once
and keep the multiples. I need the opposite of the unique() function. I expect
this should be pretty easy but I can't see it. Anyone know a solution?
Thanks in advance!


_____
Kevin Parent, Ph.D
Korea Maritime University
	[[alternative HTML version deleted]]

On Aug 7, 2013, at 10:37 PM, Kevin Parent wrote:
> Hoping someone here can help me with this small problem.
> set.seed(2013)
> 
> x<-sort(c(letters,letters[sample(26,10,1)]))
> 
> This gives a vector of 36 letters with some muliples (in this case,
g,m,s,t,u,v,x,y). Now what I need is to get rid of the ones that only occur once
and keep the multiples. I need the opposite of the unique() function. I expect
this should be pretty easy but I can't see it. Anyone know a solution?
Thanks in advance!
> 
> 
?duplicated

x[ duplicated(x) ]


David Winsemius
Alameda, CA, USA