How to find common elements from multiple vectors?

Question

Can anyone tell me how to find the common elements from multiple vectors?

a <- c(1,3,5,7,9)
b <- c(3,6,8,9,10)
c <- c(2,3,4,5,7,9)

Answer 1

A good answer already, but there are a couple of other ways to do this:

unique(c[c%in%a[a%in%b]])

or,

tst <- c(unique(a),unique(b),unique(c))
tst <- tst[duplicated(tst)]
tst[duplicated(tst)]

You can obviously omit the unique calls if you know that there are no repeated values within a, b or c.