MATLAB: Create vector from matrix without loop

Question

Hi there, I have a quick question concerning MATLAB: given A matrix A(mxn) and a Vector B(m,1) I want to create a vector C(m,1) in which each row element is the row element of A from a comlumn indexed by B. So suppose A = [ 1 2; 3 4; 5 6] and B = [2 1 1]' than C should be C = [2 35]. How can I do this using as few computational power as possible (without loops?) ?

cheers Sebastian

Answer 1

A = [ 1 2; 3 4; 5 6] 
B = [2 1 1]'
C=A(sub2ind(size(A),(1:size(A,1))',B))