ires:</strong> <code>utf8Index</code> is an element of
  <code>String(utf16)!.utf8.indices</code>.</p>

    <h4>Declaration</h4>    
    <code class="language-swift">init?(_ utf8Index: UTF8Index, within utf16: String.UTF16View)</code>

    </div></div>
</div>





<h3>Instance Methods</h3>
<div class="declaration" id="func-advancedby_">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-advancedby_">func advancedBy(<wbr>_:)</a>
        
<div class="comment collapse" id="comment-func-advancedb