请看如下正则，为何为0？？

Question

echo preg_match("/app\\common\\model\\NewsModel/",'app\common\model\NewsModel',$matches,PREG_OFFSET_CAPTURE); // 0



preg_match("/app\\common\\model\\([a-zA-Z]+)Model/",'app\common\model\NewsModel',$matches); # 错误：reg_match(): Compilation failed: unmatched parentheses at offset 27

求解

Answer 1

echo preg_match("/app\\\\common\\\\model\\\\NewsModel/",'app\common\model\NewsModel',$matches,PREG_OFFSET_CAPTURE);
preg_match("/app\\\\common\\\\model\\\\([a-zA-Z]+)Model/",'app\common\model\NewsModel',$matches);