Given a matrix A, and a matrix of column indices B, how to create a new matrix C from A and B

Consider the following 3 x 3 matrix A:

5 8 3
4 8 1
9 6 8

Consider the following 3 x 3 matrix B:

3 1 2
2 3 1
1 3 2

The rows of B contain the desired indexes of the rows of A. My goal is to create the matrix C:

3 5 8
8 1 4
9 8 6

So the rows of A are reshuffled according the indices in B. Any ideas on how to do this, preferably without loops?

Answer 1

[Jos (10584)]

A = [ 5 8 3
4 8 1
9 6 8 ]

B = [3 1 2
2 3 1
1 3 2]

% B is an array of column indices
% create the corresponding array of row indices
R = repmat(1:size(B,1),size(B,2),1).'

% the subindices (R,B) are to be transformed into linear indices
idx = sub2ind(size(A),R,B)
% which we can use to retrieve the values from A
C = A(idx)

[Youssef Khmou]

that is the correct method.