_fill</span><span class="op">(</span></span>
<span>  x <span class="op">=</span> <span class="st">""</span>,</span>
<span>  n <span class="op">=</span> <span class="cn">NULL</span>,</span>
<span>  symbol <span class="op">=</span> <span class="st">" "</span>,</span>
<span>  right <span class="op">=</span> <span class="cn">FALSE</span>,</span>
<span>  center <span class="op">=</span> <span class="cn">FALSE</span>,</span>
<span>  na <span class="op">=</span> <span class="st">"NA"</span></span>
<span><span clas