sing_n"    "missing_perc"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> $na</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> NULL</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> $options</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> NULL</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> </span>
<span class="r-out 