作者:mobiledu2502909027 | 来源:互联网 | 2018-05-20 07:39
php
class test{
public $num = 100;
}
$a = new test();
$b = clone $a;
$a->num = 200;
echo $b->num;//100
class test{
public $num = 100;
}
$a = new test();
$b = $a;
$a->num = 200;
echo $b->num;//200
//数组
$a = [1,2,3];
$b = $a;
$a[1] = 5;
var_dump($b);//[1,2,3]
$a = [1,2,3];
$b = &$a;
$a[1] = 5;
var_dump($b);//[1,5,3]
//以上就是php的深复制,浅复制,对吗?
回复内容:
php
class test{
public $num = 100;
}
$a = new test();
$b = clone $a;
$a->num = 200;
echo $b->num;//100
class test{
public $num = 100;
}
$a = new test();
$b = $a;
$a->num = 200;
echo $b->num;//200
//数组
$a = [1,2,3];
$b = $a;
$a[1] = 5;
var_dump($b);//[1,2,3]
$a = [1,2,3];
$b = &$a;
$a[1] = 5;
var_dump($b);//[1,5,3]
//以上就是php的深复制,浅复制,对吗?
class SubTest {
public $num = 100;
}
class Test {
public $child;
function __construct($child){
$this->child = $child;
}
}
$a = new Test(new SubTest());
// 这里进行浅拷贝
$b = clone $a;
$b->child->num = 200;
// 以下输出均是 200
echo $a->child->num, "\n";
echo $b->child->num, "\n";
class Test2 {
public $child;
function __construct($child){
$this->child = $child;
}
// clone 完成时,此方法会被调用,在此完成深拷贝动作
function __clone() {
$this->child = clone $this->child;
}
}
$a = new Test2(new SubTest());
// 这里进行深拷贝
$b = clone $a;
$b->child->num = 200;
// 以下输出是 100, 200
echo $a->child->num, "\n";
echo $b->child->num, "\n";
参考 PHP: 对象复制
题主的代码中包含了两个概念对象拷贝和引用。请参考 对象和引用 。
对于深复制和浅复制,不好描述,楼上的代码也体现出来了差别,在献上两张比较直观的图,这样好理解一点吧。
浅复制
:
深复制
: