s="info-desc">
<p>Return the <code class="code">n</code>-th element of the given list.
   The first element (head of the list) is at position 0.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b><ul><li><code>Failure</code> if the list is too short.</li>
<li><code>Invalid_argument</code> if <code class="code">n</code> is negative.</li>
</ul></li>
</ul>
</div>

<pre id="VALnth_opt">val nth_opt : 'a list -&gt; int -&gt; 'a option</pre><div class="info ">
<div class="info-desc">
<p>Return the <code clas