18.1.10</span> isS4()</h3>
<p>Return <code>true</code> if this object is a <code>S4</code> object.</p>
</div>
</div>
<div id="determining-type-of-object-assigned-to-robject" class="section level2" number="18.2">
<h2><span class="header-section-number">18.2</span> Determining type of object assigned to RObject</h2>
<p>One useful use of <code>RObject</code> is to determine the type of the object. To determine which type the value assigned to <code>RObject</code>, use the <code>is&lt;T&gt;()</code> function or