title: Extend the vector of results during loop
body: <p>I would like to create a vector containing my results from a loop. The results are vectors themselves, and they do not have the same length.</p>
  
  <p>Right now I have the code</p>
  
  <pre><code>totalres &lt;- NULL
  loop begins
  totalres &lt;- c(totalres,loopres)
  loop ends
  </code></pre>
  
  <p>but I've been told this is a very slow code. As I have many iterations and a big data.table I would like to know, whether there is a faster way of doing it? </p>