How to write isset with exclamation mark
<p>I just need clarification.</p>

<p>I have this code below:</p>

<pre><code>if ((!$username) &amp;&amp; (!$userid))
</code></pre>

<p>but I want to include an isset with this code. Is the correct way of typing this is below:</p>

<pre><code>if ((!isset($username)) &amp;&amp; (!isset($userid))) 
</code></pre>

<p>Thanks</p>
