pan class="op">(</span><span class="st">"n/a"</span>,<span class="st">"missing"</span><span class="op">)</span><span class="op">)</span><span class="op">)</span>
<span class="co">#&gt;   ID Subject Change</span>
<span class="co">#&gt; 1  1       7   &lt;NA&gt;</span>
<span class="co">#&gt; 2  2       8   &lt;NA&gt;</span>
<span class="co">#&gt; 3  3       9      2</span>
<span class="co">#&gt; 4  4      10      3</span>
<span class="co">#&gt; 5  5      11      4</span></code></pre></div>
<p>To recode column