MATLAB: Select random number from a variable

random number generator

how to select 4 values from already assigned variables

a= [4 5 1 2 9 7 8 1]

select 4 values from a in random fashion

out = a(randperm(numel(a),4));

ii = randperm(numel(a));
out = a(ii(1:4));

IDX = randperm(size(X,1));
RandomRows = X(IDX(1:3),:);

one way to do it is

    row = randperm(10);
    row = row(1:5);
    result = your_matrix(row,:);