How to store output of iterative statement to a matrix?

I have the following code segment

numRows=size(rulesTable,1); 
fluCertainity=[-1 100 100 75 20 25 80];
for i=1:numRows
    if rulesTable(i,1)==headache && rulesTable(i,2)==temperature
    CF=fluCertainity(i)
    end
end

Question: I want to store the fluCertainity value into the matrix 'CF' if the condition is true. How can I take CF as a matrix to store all the values from fluCertainity in case of true cases?

Thanks in advance. Rahman Ali

[EDITED, code formatted, Jan]

Answer 1

[Jan]

k = 0;
CF = zeros(numRows);   % Pre-allocate
for i=1:numRows
  if <your condition>
    k     = k + 1;
    CF(k) = fluCertainity(i);
  end
end
CF = CF(1:k);  % Crop unneded memory

Or vectorized - no need for a loop:

index = (rulesTable(:,1)==headache & rulesTable(:,2)==temperature);
CF    = fluCertainity(index);

[Rahman]

Thanks Jan. It worked.