t; 5     0       0 14.3   56     5   5</span>
<span class="co">#&gt; 6    28       0 14.9   66     5   6</span>

<span class="co"># use NaN</span>

<span class="fu"><a href="https://rdrr.io/r/utils/head.html" class="external-link">head</a></span><span class="op">(</span><span class="fu"><a href="reference/recode_na_as.html">recode_na_as</a></span><span class="op">(</span><span class="va">airquality</span>, value<span class="op">=</span><span class="cn">NaN</span><span class="op">)</span><span class="op">)</