gnette. It returns a list of two elements, containing the maximum value corresponding to <code>dep_delay</code> and <code>arr_delay</code> for each group.</p></li>
</ul>
</div>
</div>
</div>
<div id="section-10" class="section level1">
<h1></h1>
<p>Before moving on to the next section, let’s clean up the newly created columns <code>speed</code>, <code>max_speed</code>, <code>max_dep_delay</code> and <code>max_arr_delay</code>.</p>
<div class="sourceCode" id="cb15"><pre class="sourceCode r"><code class="so