ternal-link">c</a></span><span class="op">(</span><span class="st">"E"</span>,<span class="st">"E"</span>,<span class="st">"D"</span>,<span class="st">"E"</span>,<span class="st">"D"</span><span class="op">)</span><span class="op">)</span>

<span class="fu"><a href="reference/na_summary.html">na_summary</a></span><span class="op">(</span><span class="va">test2</span>,grouping_cols <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class