One thing is you cannot store 3 columns in first row and 2 columns in others.
Here is a working example of what you want to do, not the most efficient one though;
A = [ 1 23
2 53
3 44
2 45
1 78
2 12
3 56
1 28
2 94
1 26 ]
unq = unique(A(:,1)); % unique elements in 1st column
for i = 1:length(unq)
y{i} = A(A(:,1)==unq(i),2); % find the elements in the 2nd column
% that has the same number in 1st column
end
From here, to get the elements that has "unq(i)" in the first column, you do
y{i}
