l the elements of <code class="code">l</code> that
   satisfy the predicate <code class="code">p</code>, and <code class="code">l2</code> is the list of all the
   elements of <code class="code">l</code> that do not satisfy <code class="code">p</code>.
   The order of the elements in the input list is preserved.</p>
</div>
</div>
<h2 id="1_Associationlists">Association lists</h2>
<pre><span id="VALassoc"><span class="keyword">val</span> assoc</span> : <code class="type">'a -&gt; ('a * 'b) list -&gt; 'b</cod