Order an Array by Value of Key
<p>Here is my current code to add to the array:</p>

<pre><code>foreach ($query-&gt;result() as $exp) {
    $activities[] = array('type' =&gt; 'level', 'exp' =&gt; $exp-&gt;exp, 'timestamp' =&gt; $badge-&gt;timestamp);
}
</code></pre>

<p>How would I go about sorting this array according to the value of the 'timestamp' key?</p>
