>) <span class="mdzsyn-comment"># -&gt; :a</span>
(<span class="mdzsyn-symbol">arr</span> <span class="mdzsyn-number">100</span>) <span class="mdzsyn-comment"># -&gt; nil</span></code></pre><p>Note that indexing outside of the array bounds will return nil. A non-integer
key, however, will throw an error.
</p>
<h2>Setting values
</h2>
<p>To set values in an array, use either the `put` function or the `set` special.
The put function is a function that allows putting values in any associative
data structure. T