Compare/match elements of 2 vector data

I would like to compare/match elements of 2 vector data, the goal is to select the elements which element-wise from the 2 vectors are different not greater than 3. Then output are the 2 new vector with have the same length and its elements are arranged in order. The size of the 2 vectors (before processed) is arbitrary.

Ex. A = [11 38 49 84 96 117 157 176 200] 
    B = [10 28 37 48 84 157 175 200]

Compare by element which abs(A(i) - B(j)) <= 3 Then the output should be

A_new = [11 38 49 84 157 176 200] 
B_new = [10 37 48 84 157 175 200]

Can anyone guide me how to write MATLAB code for this problem? I used 2 nested loop but got stuck with empty set fault.

Thank you.

Answer 1

[Jos (10584)]

A = [11 38 49 84 96 117 157 176 200] 
B = [10 28 37 48 84 157 175 200]

D = abs(bsxfun(@minus, A(:), B(:).')) % find difference of all combinations of A and B
[iA,iB] = find(D <= 3) % which combos meet the criterion
A_new = A(iA) 
B_new = B(iB)

[Bundit Buddhahai]

Hi Jos(10584), Many thanks for your advice. I got my output when using bsxfun. It's very useful function. Regards, Bundit

Answer 2

[Image Analyst]

Seems ambiguous to me. What would you do in this case:

Ex. A = [11 38 39 84 96 117 157 176 200] 
    B = [10 28 37 48 84 157 175 200]

If the 38 moves to position 2 to be associated with the 38, then what does 39 get associated with? Is it compared to the 37, or with the 48 because the values "slide over."

What about these arrays:

Ex. A = [1 1 1 1 1 1 1] 
    B = [2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3]

[Bundit Buddhahai]

The original data of A and B are:

      A = [11 38 49 84 96 117 157 176 200] 
      B = [10 28 37 48 84 157 175 200]

The different value of each element in the vector is always greater than the matching threshold value(in this case, matching threshold = 3). To compare and match data of the 2 vectors, the matched output of 2 vectors should be:

     A_new = [11 38 49 84 157 176 200] 
     B_new = [10 37 48 84 157 175 200]

Each element with the same index of the 2 vectors has different value not greater than 3.

[Image Analyst]

Where did 49 come from? That was NOT in my example. Anyway, why not just do a pair of nested for loops?

[Bundit Buddhahai]

The third element of A is '49' not '39' (as shown in the first quote). Each adjacent element has different value more than 3.