MATLAB: How to replace elements in an array with the indices of the array’s sorted, unique values

indexingreplace elements

This is what I have (below). I am wondering if there is a better way of accomplishing the aforementioned task. Also, is there a name for this process? I don't have a formal computer science education so I'm curious.
        A  = randi(9,5,2);         % Initialize matrix.
        uA  = unique(A);            % Unique values of A.
        B   = A;                        % Output.
        for idx = 1:length(uA)          % Index to unique values, replace with
            B(B == uA(idx)) = idx;      % their sorted indices.
        end

Best Answer

All you need is the third output of unique followed by reshape:
>> [~,~,Y] = unique(A);
>> reshape(Y,size(A))
For example:
>> B % from running your code
B =
   4   5
   2   3
   1   4
   4   7
   5   6
>> [~,~,Y] = unique(A);
>> reshape(Y,size(A))
ans =
   4   5
   2   3
   1   4
   4   7
   5   6
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