Getting extension from file
<pre><code>$filename = 'mypic.gif';

// 1. The "explode/end" approach
 $ext = end(explode('.', $filename));

// 2. The "strrchr" approach
 $ext = substr(strrchr($filename, '.'), 1);

// 3. The "strrpos" approach
 $ext = substr($filename, strrpos($filename, '.') + 1);

 // 4. The "preg_replace" approach
 $ext = preg_replace('/^.*\.([^.]+)$/D', '$1',    $filename);

 // 5. The "never use this" approach.    
  //   From: http://php.about.com/od/finishedphp1/qt/file_ext_PHP.htm
 $exts = split("[/\\.]", $filename);
 $n = count($exts)-1;
 $ext = $exts[$n];
</code></pre>

<p>I have trouble undertand the step 5, anyone able to explain? 
And also What does it mean by never use approach?</p>
