lass="op">(</span><span class="va">x4</span><span class="op">)</span><span class="op">)</span></span>
<span><span class="co">#&gt; [1] Left     Middle   Right    Apolitic</span></span>
<span><span class="co">#&gt; Levels: Apolitic Left Middle Right</span></span></code></pre></div>
<p>This is almost identical, but differs from <code>x5</code> with
respect to the level orders. It happens because the missing value -91,
coerced to a valid value, becomes the first in the order of the
categories while normally, a