Conditional replacement of array values from another array

Hello,

I'm trying to resolve what I thought would be a simple issue. To simplify the problem, I have two matrices A and B,

I want to write a loop that scans for values in A that are 500 and then replace then in order with the values from B. I tried the included code, but it just didn't work out.

Any help would be appreciated!

A = [500; 500; 40; 50; 500];
B = [20; 30; 60]

for n = 1:5
    for m = 1:3
        if A(n,1) == 500
            A(n,1) = B(m,1);
        else
            A(n,1) = A(n,1);
        end
    end
end

%Desired result is A = [20; 30; 40; 50; 60]

Answer 1

[Tommy]

Do you need a loop?

If you know there are exactly as many 500s in A as there are values in B:

A(A==500) = B;

If there may be more values in B:

A(A==500) = B(1:sum(A==500));

If there may be more 500s in A:

A(find(A==500, numel(B))) = B;

If you can't be sure:

A(find(A==500, numel(B))) = B(1:min(numel(B), sum(A==500)));

[Kevin Su]

Thanks for such a quick response!

I did not know how many 500s there were in A; I did manage to find a solution; although I'm unsure whether a while loop would be good practice for this.

m = 1;
len = length(B);
while m <= len
    for n = 1:5
        if A(n,1) == 500
            A(n,1) = B(m,1);
            m = m + 1;
        else
            A(n,1) = A(n,1)
        end
    end
end