91) NA(-91) NA(-92)      NA</span></span>
<span><span class="co">#&gt; Missing values: -92, -91</span></span></code></pre></div>
<p>This custom function benefits from an additional argument <code class="sourceCode r">empty.last</code> (internally passed to the
ordering function), to allow sorting within the missing values:</p>
<div class="sourceCode" id="cb12"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span class="fu"><a href="https://rdrr.io/r/base/sort.html" class="external-link"