MATLAB: Find unique numbers in a set

exerciseunique

This is, lol, I guess another personal exercise (sort of, although it is kind towards solving a bigger problem).
Anyway I'm having trouble figuring out how to find the unique numbers in an array/set.
Now, I KNOW about the unique function. It's cool. I'm even using it elsewhere. But I am also interested in how it is written, and the unique.m file in the matlab toolbox is basically incomprehensible to me.
So far I have started out really simple. What I am trying to do is simply look at an array, see if a number is repeated (literally true false atm), then stick that number and it's occurrence boolean into a cell. Here is the code so far:
%What we want to do is fill a cell as follows 
%C=cell{1,2,N(=Unique values in [S])} 
%Where 
%C{1,1,N} = [N_unique] (N_unique => Nq)
%C{1,2,N} = [Occurence of N_unique] (=> On(Nq))
%Such that 
%C{:,:,1} = 

%[Nq(1)] [Oc(Nq(1))] 
%...
%C{:,:,N} = 
%[Nq(N)] [Oc(Nq(N))] 
%
%This requires an index N that iterates only once for every number,
%whether or not it occurs more than once. 
%This also requires another index Oc that iterates once for every time
%its respective number occurs. Oc must be at least one for every number. 
%So, the array [267 308 267] should produce 
%C{:,:,1} = 
%[267] [2] 
%C{:,:,2} = 
%[308] [1] 
A = [267 267 308]; 
N = 1; %Index for each unique number
On = 0; 
    for i = 1:length(A)    
        for j = 1:length(A)        
            if A(i) == A(j) && i~=j 
                %fprintf('%d %d %d %d %d\n', A(i),i, A(j),j,1); 
                %A(i) has occured more than once 
              On = 1; %True for On(A(i))             
          elseif A(i) ~= A(j)
              fprintf('%d %d %d %d %d\n', A(i),i, A(j),j, 0); 
              %A(i) has not occured more than once 
              On = 0; %False for On(A(i))             
          end      
          C{1,1,N} = A(i); 
          C{1,2,N} = On;          
      end          
  end
Now this code is pretty unfinished, obviously. For example, N doesn't even increase. It just sits there the whole time at 1. This is because I can't figure out how to get it to iterate once PER NUMBER, as opposed to, for example, per loop.
Also Oc right now is just true/false, not the actual occurrence rate.
Anyway sorry for wasting time but I'm just really frustrated and curious about how to do this.

Best Answer

If I were writing a 'unique' function, the first operation would be to sort the set. There are many efficient routines to do that. After that it is a breeze picking out only those elements in the sorted sequence that are unique: pick the first (or last) of each consecutive subsequence of equal elements.
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