values inside <code>structure</code> can also be
<code>integer(x)</code> or <code>double(x)</code>. In particular, if one or more
dimensions is zero, <code>integer()</code> can be put inside
<code>structure</code>. For instance, the following example is supported by
the dump format.</p>
<pre><code>y &lt;- structure(integer(), .Dim = c(2,0))</code></pre>
</div>
<div id="matrix--and-vector-valued-variables" class="section level2">
<h2><span class="header-section-number">21.5</span> Matrix- and Vector-Valued V