PHP best way to check whether a string is empty or not
<p>I've seen a lot of php code that does the following to check whether a string is valid by doing:</p>

<p>$str is a string variable.</p>

<pre><code>if (!isset($str) || $str !== '') {
  // do something
}
</code></pre>

<p>I prefer to just do</p>

<pre><code>if (strlen($str) &gt; 0) {
  // something
}
</code></pre>

<p>Is there any thing that can go wrong with the second method?  Are there any casting issues I should be aware of?</p>
