Different approaches to get file extentions by PHP

http://cowburn.info/2008/01/13/get-file-extension-comparison/
$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 “pathinfo” approach

   $filename = 'mypic.gif';
   $ext = pathinfo($filename, PATHINFO_EXTENSION);