<?php $file = "/home/lvyaozu/backup_20080115.txt"; for($i=1; $i < 6; $i++) { $func = 'get_file_ext_' . $i; var_dump($func($file)); } function get_file_ext_1($file) { return strtolower(trim(substr(strrchr($file, '.'), 1))); } function get_file_ext_2($file) { return strtolower(trim(pathinfo($file, PATHINFO_EXTENSION))); } function get_file_ext_3($file) { return strtolower(trim(substr($file, strrpos($file, '.')+1))); } function get_file_ext_4($file) { return strtolower(trim(array_pop(explode('.', $file)))); } function get_file_ext_5($file) { $tok = strtok($file, '.'); while($tok !== false) { $return = $tok; $tok = strtok('.'); } return strtolower(trim($return)); } ?> 本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/lvyaozu/archive/2009/06/03/4237628.aspx