MATLAB: How to find the number of occurrences of each pair in a matrix

count occurrencespairs

Suppose my
A = [1 2 3; 
     2 3 1; 
     2 1 3] 
 % where any digit won't repeat in the same row.
 % I need to find out the number of occurrences of each pair.
Expected output:
Pair(1,2) = 1 occurence; 
Pair(2,1) = 1;
Pair(2,3) = 2;
Pair(3,2) = 0;
Pair(3,1) = 1; 
Pair(1,3) = 1;
I was trying this code
    for n = 2:3
    [j,i]=ind2sub(fliplr(size(A)),  strfind(reshape(A.',1,[]),[1 n]).');
    C = [i,j];
    d = numel(C(j));
    T9 = table(1, n, d)
    end
error occurs when the second row ends with 1 and the third row begins with 2.

Best Answer

A = [1 2 3; 
     2 3 1; 
     2 1 3];
u = unique(A);
P = nchoosek(u,2);
P = [P;fliplr(P)];
[~,J] = ismember([A(:,1:2); A(:,2:3)],P,'rows');
n = accumarray(J(:),1,[size(P,1) 1]);
% 
for k=1:size(P,1)
    fprintf('Pair %s, %d time\n',mat2str(P(k,:)),n(k));
end
Output
Pair [1 2], 1 time
Pair [1 3], 1 time
Pair [2 3], 2 time
Pair [2 1], 1 time
Pair [3 1], 1 time
Pair [3 2], 0 time
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