这两段代码有什么区别?
<?php
$object1 = new User();
//^^
$object1->name = "Hello";
echo $object1->name;
class User {}
?>
和:
<?php
$object1 = new User;
//^
$object1->name = "Hello";
echo $object1->name;
class User {}
?>
我得到相同的输出:
Hello
那么,如果我使用或不使用括号,有什么不同吗:
$object1=new User;
最佳答案
完全一样,你可以比较这两个脚本的操作码:
1 个脚本:
$object1=new User();
$object1->name="Hello";
echo $object1->name;
class User {}
操作码:
line # * op fetch ext return operands
---------------------------------------------------------------------------------
3 0 > FETCH_CLASS 4 :0 'User'
1 NEW $1 :0
2 DO_FCALL_BY_NAME 0
3 ASSIGN !0, $1
4 4 ASSIGN_OBJ !0, 'name'
5 OP_DATA 'Hello'
5 6 FETCH_OBJ_R $5 !0, 'name'
7 ECHO $5
6 8 NOP
9 > RETURN 1
2 脚本:
$object1=new User;
$object1->name="Hello";
echo $object1->name;
class User {}
操作码:
line # * op fetch ext return operands
---------------------------------------------------------------------------------
3 0 > FETCH_CLASS 4 :0 'User'
1 NEW $1 :0
2 DO_FCALL_BY_NAME 0
3 ASSIGN !0, $1
4 4 ASSIGN_OBJ !0, 'name'
5 OP_DATA 'Hello'
5 6 FETCH_OBJ_R $5 !0, 'name'
7 ECHO $5
6 8 NOP
9 > RETURN 1
关于php - 带括号和不带括号的实例化有区别吗?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28914283/