onethink php数组根据数值字段排序函数

<?php
/*首页显示五条数据排序函数*/
public function remenwenti(){
    $remenwenti = M('AqWen')->order('id desc')->select();
    foreach ($remenwenti as $key => $value) {
        $num = M('AqDa')->where(array('wen_id'=>$value['id']))->count();
        $remenwenti[$key]['num'] = $num;
        $remenwenti[$key]['tag'] = explode(",",$value['tag']);
    }
    $remenlist = remenpaixu($remenwenti, 'num');//热门排序处理
    $this->remenwenti = array_slice($remenlist,0,5);//问答栏目首页热门显示5条处理
}
/*列表页分页排序处理*/
public function remenliebiao(){
    $remenwenti = M('AqWen');
    $count  = $remenwenti->field(true)->count();// 查询满足要求的总记录数
    $Page   = new \Think\Page($count,50);// 实例化分页类 传入总记录数和每页显示的记录数(25)
    $show   = $Page->show();// 分页显示输出
    // 进行分页数据查询 注意limit方法的参数要使用Page类的属性
    $list = $remenwenti->field(true)->order('id desc')->limit($Page->firstRow.','.$Page->listRows)->select();

    foreach ($list as $key => $value) {
        $num = M('AqDa')->where(array('wen_id'=>$value['id']))->count();
        $list[$key]['num'] = $num;
    }
    $remenlist = remenpaixu($list, 'num');//热门排序处理
    $this->assign('wenDaList',$remenlist);// 赋值数据集
    $this->assign('page',$show);// 赋值分页输出
    $this->display();
}
/*数值字段排序处理函数*/
function remenpaixu($arr,$field){
    $sort = array(
        'direction' => 'SORT_DESC', //排序顺序标志 SORT_DESC 降序; SORT_ASC 升序  
        'field' => $field,           //排序字段
    );
    $arrSort = array();
    foreach($arr as $uniqid => $row){ 
        foreach($row as $key=>$value){
            $arrSort[$key][$uniqid] = $value;
        }
    }
    if($sort['direction']){
        array_multisort($arrSort[$sort['field']], constant($sort['direction']), $arr);  
    }
    return $arr;
}