Filling vector with a condition.

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!!

Answer 1

[Stephan M. H.]

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

[Javier]

Gracias totales!! Thank you!

Answer 2

[John Doe]

Like this?

A = [1 2 -3 0 4 0 -5 0 6];
B = 10:19;
C = zeros(1,length(A));

C(A>0) = B(A>0)

C =

      10    11     0     0    14     0     0     0    18

[Javier]

Thank you!