Try this:
Col1 = randperm(300); % Create Column 1
Col2 = randi(9, 1, 300); % Create Column 2
M = [Col1(:) Col2(:)]; % Create Matrix
Gather = accumarray(M(:,2), M(:,1), [], @(x){x.'}); % Cell Array With Desired Information
AB = {(1:9).', Gather};
That should work. You will need to keep ‘AB’ as a cell array because there are different numbers of columns in each row. You might be able to use a structure to store this information, however I doubt that a table would work correctly.
Experiment to get the result you want.
