MATLAB: How to return the indices of randomly sampled matrices

indexingMATLABmatrix indicesrandom

Hello. I have two large matrices of equal size. I'm currently using randsample to put randomly selected values of one of the matrices into a new vector. But now I need to also identify the indices of the randomly selected values from the one matrix and correspond it to the same indices in the other matrix.
For example:
A = [1 2 3 4 5; 6 7 8 9 10; 11 12 13 14 15]
B = [16 17 18 19 20; 21 22 23 24 25; 26 27 28 29 30]
If I randomly select from A:
Arand = [3 6 10 1 15 11]
How do I get:
Brand = [18 21 25 16 30 26] where the values of Brand have the same indices in B as Arand has in A?
Do I need to abandon my use of randsample altogether?
Thanks for your help!

Best Answer

Especially if A has duplicated scores, it might be better to randomly sample the positions and then take elements of both arrays from those random positions:
nelements = numel(A);
SampleSize = 3;
randices = randsample(1:nelements,SampleSize,false);
randAs = A(randices)
randBs = B(randices)
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