MATLAB: Filling vector with a condition.

conditionfilling vectorifvectos

Hi.
I have two vectors A and B of the same length
I wan´t to create a new vector containing the same numbers of B, but only if the same element in A was a number>0, if not, i want to put a zero in that element.
How can i do this? Could you help me?
Thank you in advance!!

Best Answer

Hi Javier,
as far as I understood your question you want to create a new vector with
 for i=1:lenght(A)
   if A(i)>0
     C(i) = B(i)
   end
 end
This could be done in with the for loop above, but the fastest way should be via logical indexing.
 C = zeros(size(A));
 flag_a = A >0   % is logical 1 where elements are bigger zero 
 C(flag_a) = B(flag_a);
best, Stephan
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