MATLAB: How to do something like A(:,B(:))

Question

Hello everybody,

I have a matrix A of size n x p, e.g. 10*4

A =
    0.2760    0.7513    0.8407    0.3517
    0.6797    0.2551    0.2543    0.8308
    0.6551    0.5060    0.8143    0.5853
    0.1626    0.6991    0.2435    0.5497
    0.1190    0.8909    0.9293    0.9172
    0.4984    0.9593    0.3500    0.2858
    0.9597    0.5472    0.1966    0.7572
    0.3404    0.1386    0.2511    0.7537
    0.5853    0.1493    0.6160    0.3804
    0.2238    0.2575    0.4733    0.5678

and a vector B (1 x n), e.g.

B =
     2     2     4     4     1     2     2     3     3     4

and I would like to build a vector C (1 x n) where C(k) = A(k,B(k)) (in my example I would like to get C = [0.7513 0.2551 0.5853 …….] I thought I was pretty comfortable with matlab syntax but I'm lost there ! 🙂 if anyone has any idea …

Answer 1

nm=size(A)
C=A(sub2ind(nm,1:nm(1),B))