MATLAB: Compare matrices with different dimension

ismember

Hi,
A = [100123 1 1 50; 
     100123 1 2 53; 
     100123 1 3 55; 
     100456 2 1 78; 
     100456 2 2 75;
     100789 1 1 80]
B = [100123 1 56; 
     100456 2 76]
Comparing the 1st and 2nd columns of A and B, I've to compute the difference between each value in the 4th comlumn of A and the values in the 3th column of B.
In the case to compute (A – B), the expected result is a Matrix as
C = [100123 1 1 -6; 
     100123 1 2 -3; 
     100123 1 3 -1; 
     100456 2 1  2; 
     100456 2 2 -1]
Tnx for any suggestion

Best Answer

You could try this:
>> X = bsxfun(@eq,A(:,1).',B(:,1));
>> Y = bsxfun(@minus,A(:,4).',B(:,3));
>> Z = [A(any(X,1),1:3),Y(X)]
Z =
        100123           1           1          -6
        100123           1           2          -3
        100123           1           3          -1
        100456           2           1           2
        100456           2           2          -1
It returns only the rows of A for which the first element matches any first row element in B, and in the last column gives the difference of corresponding end elements of A and B.
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