&gt; char -&gt; int option</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code">index_from_opt&nbsp;s&nbsp;i&nbsp;c</code> is the index of the first occurrence of <code class="code">c</code>
    in <code class="code">s</code> after position <code class="code">i</code> (if any).</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.05</li>
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">i</code> is not a valid position in <code class="code">s</code>.</li>
<