pan class="va">dfm</span></span>
<span><span class="co">#&gt;   x1      x2</span></span>
<span><span class="co">#&gt; 1  a       1</span></span>
<span><span class="co">#&gt; 2  b       2</span></span>
<span><span class="co">#&gt; 3  c       3</span></span>
<span><span class="co">#&gt; 4  d       4</span></span>
<span><span class="co">#&gt; 5  e       5</span></span>
<span><span class="co">#&gt; 6  f NA(-91)</span></span>
<span><span class="co">#&gt; 7  g NA(-91)</span></span></code></pre></div>
<p>If users 