//rdrr.io/r/utils/head.html" class="external-link">head</a></span><span class="op">(</span><span class="fu"><a href="reference/recode_as_na_if.html">recode_as_na_if</a></span><span class="op">(</span><span class="va">airquality</span>,sign<span class="op">=</span><span class="st">"gt"</span>, percent_na<span class="op">=</span><span class="fl">20</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    NA     190  