="type">string -&gt; char -&gt; int</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">index&nbsp;s&nbsp;c</code> is <a href="String.html#VALindex_from"><code class="code"><span class="constructor">String</span>.index_from</code></a><code class="code">&nbsp;s&nbsp;0&nbsp;c</code>.</p>
</div>
</div>

<pre><span id="VALindex_opt"><span class="keyword">val</span> index_opt</span> : <code class="type">string -&gt; char -&gt; int option</code></pre><div class="info ">
<div class="info-