title: PASCAL string to array
body: <p>How can I convert a string of numbers like for example <code>'21354561321535613'</code> into digits and store them in an array?</p>
  <p>Each digit should be turned into an integer element in the array, so the string <code>'21354561321535613'</code> should result in:</p>
  <pre><code>[2, 1, 3, 5, 4, 5, 6, 1, 3, 2, 1, 5, 3, 5, 6, 1, 3]
  </code></pre>