PHP 二维数组根据某个字段排序

<?php  /**  * 二维数组根据某个字段排序  * 功能：按照用户的年龄倒序排序  * @author ruxing.li  */  header('Content-Type:text/html;Charset=utf-8');  $arrUsers = array(      array(              'id'   => 1,              'name' => '张三',              'age'  => 25,      ),      array(              'id'   => 2,              'name' => '李四',              'age'  => 23,      ),      array(              'id'   => 3,              'name' => '王五',              'age'  => 40,      ),      array(              'id'   => 4,              'name' => '赵六',              'age'  => 31,      ),      array(              'id'   => 5,              'name' => '黄七',              'age'  => 20,      ),  );       $sort = array(          'direction' => 'SORT_DESC', //排序顺序标志 SORT_DESC 降序；SORT_ASC 升序          'field'     => 'age',       //排序字段  );  $arrSort = array();  foreach($arrUsers AS $uniqid => $row){      foreach($row AS $key=>$value){          $arrSort[$key][$uniqid] = $value;      }  }  if($sort['direction']){      array_multisort($arrSort[$sort['field']], constant($sort['direction']), $arrUsers);  }    var_dump($arrUsers);    /* 输出结果：  array (size=5)   0 =>      array (size=3)       'id' => int 5       'name' => string '黄七' (length=6)       'age' => int 20   1 =>      array (size=3)       'id' => int 2       'name' => string '李四' (length=6)       'age' => int 23   2 =>      array (size=3)       'id' => int 1       'name' => string '张三' (length=6)       'age' => int 25   3 =>      array (size=3)       'id' => int 4       'name' => string '赵六' (length=6)       'age' => int 31   4 =>      array (size=3)       'id' => int 3       'name' => string '王五' (length=6)       'age' => int 40  */