二维数组，根据二维数组内的元素进行排序

protected function sort($arrUsers){
 
        
    $sort = array(    
            'direction' => 'SORT_ASC', //排序顺序标志 SORT_DESC 降序；SORT_ASC 升序    
            'field'     => 'distance',       //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);    
    }    
         
    return $arrUsers;
 }