">$</span>d <span class="op">==</span><span class="st"> </span><span class="dv">-99</span>] &lt;-<span class="st"> </span><span class="ot">NA</span></span>
<span id="cb24-6"><a href="Intro.html#cb24-6"></a></span>
<span id="cb24-7"><a href="Intro.html#cb24-7"></a>df</span></code></pre></div>
<pre><code>## # A tibble: 5 x 4
##       a     b     c     d
##   &lt;dbl&gt; &lt;dbl&gt; &lt;dbl&gt; &lt;dbl&gt;
## 1     3     3     3     1
## 2     3     2     3     1
## 3     1    NA     1     2
## 4     1    NA  