How do I merge vectors?

I have a 10X1 vector A=[1;3;7;10;12;14;15;18;20;21] and a 10X1 vector B=[3;12;15;18;20;0;0;0;0;0]. Is there a way to come up with a 10X2 vector C such that the equal elements in each vector sit at the same row in vector C? I want to retain all elements of vector A in vector C and keep only the elements from vector B that have values equal to the one elements in vector A. Ideally, My final vector C would look something like this: C=[1 0;3 3;7 0;10 0;12 12;14 0;15 15;18 18;20 20;21 0]. Any thoughts?

Answer 1

[BhaTTa]

To achieve this, you want to create a 10×2 matrix C where:

• The first column contains all elements from vector A.
• The second column contains the elements from vector B, but only those that have corresponding matches in A and in the same position.

You can accomplish this by iterating over the elements of vector A and finding the corresponding matches in vector B. Here's how you can do it in MATLAB:

% Define the input vectors
A = [1; 3; 7; 10; 12; 14; 15; 18; 20; 21];
B = [3; 12; 15; 18; 20; 0; 0; 0; 0; 0];

% Initialize the output matrix C
C = zeros(length(A), 2);

% Fill the first column of C with elements from A
C(:, 1) = A;

% Loop through each element in A to find matches in B
for i = 1:length(A)
    % Find the index of A(i) in B
    index = find(B == A(i));
    
    % If a match is found, place it in the second column of C
    if ~isempty(index)
        C(i, 2) = B(index(1));
    else
        % If no match is found, ensure the second column is zero
        C(i, 2) = 0;
    end
end

% Display the result
disp(C);