[R] How to get a subscript of a vector?

[arun]

Hi,
?which()
 which(A==2)
#[1]  3  7 10
A.K.

Suppose there is a vector 
A <- c(1,3,2,6,7,8,2,1,3,2). 

Now, I want to get the subscript of elements of A which equal 2. 

How can I do it ?