Check if a class has a field by string
<p>I would Google this, but honestly I have no idea what to search for</p>

<p>Say I have this class</p>

<pre><code>class a
{
    public $a_a, $a_b, $a_c;
}

$true = "a_a";
$false = "a_e";
</code></pre>

<p>How do I use the strings to prove that the class contains the field a_a, but not a_e ?</p>

<p>Thanks</p>
