1、寫一個函數對二維數組的排序（php）

<?php /*** 根據某列對二維數組進行排序* @param  [type] $arr  [要排序的數組]* @param  [type] $row  [排序依據列]* @param  string $type [asc表示正序，默認值，desc表示逆序]* @return [type]       返回排序好的數組*/function array_sort($arr, $row, $type = 'asc'){$arr_temp = array();foreach ($arr as $v) {$arr_temp[$v[$row]] = $v;}if($type  == 'asc'){ksort($arr_temp); //ksort()、函數對關聯數組按照鍵名進行升序排序}elseif($type == 'desc'){krsort($arr_temp); //krsort()、函數將數組按照鍵逆向排序標志，為數組值保留原來的鍵}else{}return $arr_temp;}$person = array(array('id' => 2,'name' => 'zhangsan', 'age' => 23),array('id' => 5,'name' => 'lisi', 'age' => 28),array('id' => 3,'name' => 'apple', 'age' => 17));

$person = array_sort($person,'name');PRint_r($person);

2、寫5個不同的自己的函數，來獲取一個全路徑的文件的擴展名，允許封裝php庫中已有的函數

<?php $path = str_replace('//', '/', _FILE_);//$path 定義根目錄地址//方法一function ext_name1($path)(return strrchr($path,'.');)//方法二function ext_name2($path){return substr($path, strrops($path,'.'));}//方法三function ext_name3($path){$path_parts = pathinfo($path);return $path_parts['extension'];}//方法四function ext_name4($path){$arr = explode('.', $path);}//方法五function ext_name5($path){$pattern = '/^[^/.]+/.([/w]+)$/';return preg_replace($pattern, '${1}', basename($path));}