-19"><a href="#cb19-19" aria-hidden="true"></a><span class="co"># [1] &quot;x&quot; &quot;y&quot; &quot;z&quot;</span></span></code></pre></div></li>
</ol>
<div id="summary" class="section level2">
<h2>Summary</h2>
<div id="the-operator" class="section level4 bs-callout bs-callout-info">
<h4 class="bs-callout bs-callout-info">The <code>:=</code> operator</h4>
<ul>
<li><p>It is used to <em>add/update/delete</em> columns by reference.</p></li>
<li><p>We have also seen how to use <code>:=</code> along with <co