de>8</code>,
and 3-D array variable <code>ar_d3</code> contains (an array which contains an array which contains) value <code>9</code>,
the JSON representation is:</p>
<pre><code>{ &quot;ar_d1&quot; : [7],
  &quot;ar_d2&quot; : [[8]],
  &quot;ar_d3&quot; : [[[9]]]
}</code></pre>
<p>However, in the case where variable <code>d</code> is <code>0</code>,
<code>ar_d1</code> is empty, i.e., it contains no values,
as is <code>ar_d2</code>, <code>ar_d3</code>,
and the JSON representation is</p>
<pre><code>{ &quot;d