laravel中报错之preg_replace()

preg_replace(): Parameter mismatch, pattern is a string while replacement is an array

纠结半天：问题出在[]那里（去掉就ok）

public function updateEmployees(Request $request)
{
    $employees = array(
        'user_name' => $request->user_name,
        'user_email' => $request->user_email,
        'user_phone' => $request->user_phone,
        'user_lvl_id' => $request->user_lvl_id,
        'department_id' => $request->department_id,
        'last_update_date' => Carbon::now(),
        'last_update_user_id' => $this->uid,
    );
    $res=DB::table('admins')->where('user_id', $request->user_id)->update($employees);
    if($res){
        $message['status']='success';
        $message['msg']='更新成功!';
    }
    else{
        $message['status']='error';
        $message['msg']='更新失败!';
    }
    return redirect('admin/employee')->with('message',$message);
}

ok！