MATLAB: How to detect which rows are left in the matrix when the unique function is used to eliminate the repeated rows

Question

Hi, I have

a= 1     1
   1     2
   1     2
   1     2
   1     1
   1     2
 b=unique(a,'rows');
 >>b=   1     1
        1     2

I want to know which rows are [1 1] and [ 1 2] in 'a'. Output can be 1 and 2, 1 and 3, or 5 and 6. As long as the first number represents the row of [1 1] and the second number for [1 2].

How am i going to do this? Thank you.

Answer 1

[C,ia,ic] = unique(A,'rows')