Check for unique elements

Question

just a simple question. I have a data frame(only one vector is shown) that looks like:

cln1
A
b
A
A
c
d
A
....

I would like the following output:

cln1
b
c
d

In other words I would like to remove all items that are replicated. The functions "unique" as well as "duplicated" return the output including the replicated element represented one time. I would like to remove it definitively.

Answer 1

You can use setdiff for that :

R> v <- c(1,1,2,2,3,4,5)
R> setdiff(v, v[duplicated(v)])
[1] 3 4 5