">p x</code> holds. Otherwise returns <code class="code">None</code><br>
<b>Since</b> 0.3.4<br>
</div>

<pre><span id="VALlookup"><span class="keyword">val</span> lookup</span> : <code class="type">?cmp:'a <a href="Barray_slice.html#TYPEord">ord</a> -> 'a -> 'a <a href="Barray_slice.html#TYPEt">t</a> -> int option</code></pre><div class="info ">
Lookup the index of some value in a sorted array.<br>
<b>Returns</b> <code class="code">None</code> if the key is not present, or
      <code class="code">Some i</c