Creating a loop to search for matching values in two matrices

I have two csv files. A is 55473 x 10 and B is 484 x 3. I want to create a loop that goes through column 5 in A, and when the value in the cell equals a value in column 1 in B, i want to multiply it by column 2 and column 3 of the same row in B. I want to repeat this for all values in column 5 of A.

Answer 1

[Azzi Abdelmalek]

You can do it without a for loop

[ii,jj]=ismember(A(:,5),B(:,1));
id=nonzeros(jj);
A(ii,5)=A(ii,5).*B(id,2).*B(id,3);

Answer 2

[Azzi Abdelmalek]

%-------Example-----------------
A=randi(10,55473,10);
B=randi(10,484,3); 
%----------------------------------
for k=1:size(A,1)
  idx= find(ismember(B(:,1),A(k,5)),1);
  if ~isempty(idx);
      A(k,5)=A(k,5)*B(idx,2)*B(idx,3);
  end
end

[mcl1993]

Thanks, can you explain what the line idx = find(ismember(B(:,1),A(k,5)),1); means?

[Azzi Abdelmalek]

doc find
doc ismember