ml" class="external-link">head</a></span><span class="op">(</span><span class="fu"><a href="reference/drop_na_if.html">drop_na_if</a></span><span class="op">(</span><span class="va">airquality</span>, percent_na <span class="op">=</span> <span class="fl">24</span>, keep_columns <span class="op">=</span> <span class="st">"Ozone"</span><span class="op">)</span><span class="op">)</span>
<span class="co">#&gt;   Ozone Solar.R Wind Temp Month Day</span>
<span class="co">#&gt; 1    41     190  7.4   67     5   1<