Fill matrix with zeros

Hello, i have two matrices, one has fixed size 100x1 and the second one changes lets say could be 97x4 or 103x4, i want to multiply just the first columns of these two, but how can i multiply them, i just want to fill the rest of the rows with zeros if its less than 100 ,and i want to remove the last three columns if it is more than 100, Any ideas? Thank you

Answer 1

[Mohammad Abouali]

A: is the Fixed Sized Matrix

B: is the Variable Sized Matrix

A(:,1) .* [B(1:min(size(A,1),size(B,1)),1); zeros(size(A,1)-size(B,1),1)]

[Cladio Andrea]

i was exactly looking for this. Thank you Mohammad!!

Answer 2

[Image Analyst]

Try this:

% Sample data
matrix1 = randi(9, 100, 1);
matrix2 = randi(9, 97, 4);
[rows, columns] = size(matrix2)
if rows > 100
    % Crop off any rows more than 100
    matrix2 = matrix2(1:100, :);
elseif rows < 100
  % Pad with rows of zero.
    matrix2(100,:) = 0;
end
% Now multiply.
col1Product = matrix1 .* matrix2(:, 1);

[Cladio Andrea]

Thanks a lot, In 10 minutes i got 2 perfect answer thank you!!