title: how to extract the 2nd number in a string
body: <p>I want to extract only the second number (in order) from a string.</p>
  <pre class="lang-r prettyprint-override"><code>string = &quot;vancomycin 1G IV 3 times a day over 1 hour.&quot;
  </code></pre>
  <p>desired output = 3</p>