-link" href="#index-categorical-6"> &para;</a></span></dt>
<dd>
<p>Categorical variable array.
</p>
<p>A <code class="code">categorical</code> array represents an array of values of a categorical
variable. Each <code class="code">categorical</code> array stores the element values along
with a list of the categories, and indicators of whether the categories
are ordinal (that is, they have a meaningful mathematical ordering), and
whether the set of categories is protected (preventing new categories
from being