Display array's elements grouped by date
<p>I have an array $histories:</p>

<pre><code>Array (
Array ([id] =&gt; 1, [created] =&gt; 2012-12-20 22:40, [message] =&gt; 'Message1 to display here'),
Array ([id] =&gt; 2, [created] =&gt; 2012-12-20 22:40, [message] =&gt; 'Message2 to display here'),
Array ([id] =&gt; 3, [created] =&gt; 2012-12-20 22:40, [message] =&gt; 'Message3 to display here'),
Array ([id] =&gt; 4, [created] =&gt; 2012-12-20 21:30, [message] =&gt; 'Message4 to display here'),
Array ([id] =&gt; 5, [created] =&gt; 2012-12-20 21:30, [message] =&gt; 'Message5 to display here'),
Array ([id] =&gt; 6, [created] =&gt; 2012-12-20 20:20, [message] =&gt; 'Message6 to display here'),
);
</code></pre>

<p>I would like to display messages [message] grouped by date [created] field.</p>

<p>like</p>

<pre><code>2012-12-20 22:40
======================
Message1
Message2
Message3

2012-12-20 21:30
======================
Message4
Message5
</code></pre>

<p>I know there is a function array_count_values() that could help.</p>
