DT_n also gets updated</span></span>
<span id="cb19-10"><a href="#cb19-10" aria-hidden="true"></a>DT_n</span>
<span id="cb19-11"><a href="#cb19-11" aria-hidden="true"></a><span class="co"># [1] &quot;x&quot; &quot;y&quot; &quot;z&quot;</span></span>
<span id="cb19-12"><a href="#cb19-12" aria-hidden="true"></a></span>
<span id="cb19-13"><a href="#cb19-13" aria-hidden="true"></a><span class="co">## use `copy()`</span></span>
<span id="cb19-14"><a href="#cb19-14" aria-hidden="true"></a>DT_n =<span class="st"> 