PHP获取文件后缀名的几种方法

<?PHP获取文件后缀名的几种方法1：function get_file_type($filename){    $type = substr($filename, strrpos($filename, ".")+1);    return $type;}PHP获取文件后缀名的几种方法2：function get_file_type($filename) {      $type = pathinfo($filename);      $type = strtolower($type["extension"]);      return $type; }PHP获取文件后缀名的几种方法3：function get_file_type($filename) {      $type =explode("." , $filename);      $count=count($type)-1;     return $type[$count]; } ?>