PHP递归获取下级数组，可指定ID，一维数组

    /**
     * 递归获取下级数组 返回一维数组
     * @param array $data
     * @param number $pid
     * @param array $SonNode
     * @return array
     */
    public function getSonNode($data,$pid=0,$SonNode = array()){
        $SonNode[] = $pid;
        foreach($data as $k=>$v){
            if($v['source_member'] == $pid){
                $SonNode = $this->getSonNode($data,$v['member_id'],$SonNode);
            }
        }
        unset($SonNode[0]);
        return $SonNode;
    }