MATLAB: How can sort the numbers according to the numbners in the first column

sorting

suppose i have a matrix where the first column is x(:,1)=[ 1 1 1 2 2 1 3 3 ] and second column is x(:,2)=[ 2 3 2 4 6 9 7 8 9];
i want different matrices which give me the numbers corresponding to 1, 2 and so on. in this case i need three different matrices where the first one will give me [2 3 2 7]
second will give [4 6] and third is [8 9]

Best Answer

A general solution using accumarray:
>> x = [1,2;1,3;1,2;2,4;2,6;1,7;3,8;3,9]
x =
   1   2
   1   3
   1   2
   2   4
   2   6
   1   7
   3   8
   3   9
>> C = accumarray(x(:,1),x(:,2),[],@(v){v});
>> C{:}
ans =
   2
   3
   2
   7
ans =
   4
   6
ans =
   8
   9
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