PHP object cloning clone usage example-PHP Tutorial-php.cn

PHP object cloning clone usage example

高洛峰

Release： 2023-03-03 20:02:01

Original

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The example in this article describes the usage of PHP object cloning clone. Share it with everyone for your reference, the details are as follows:

Shallow cloning: only clone the non-object non-resource data in the object, that is, the attributes in the object store the object type, then there will be incomplete cloning

<?php
class B{
 public $val = 10;
}
class A{
 public $val = 20;
 public $b;
 public function __construct(){
  $this->b = new B();
 }
}
$obj_a = new A();
$obj_b = clone $obj_a;
$obj_a->val = 30;
$obj_a->b->val = 40;
var_dump($obj_a);
echo &#39;<br>&#39;;
var_dump($obj_b);

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Run The results are as follows:

object(A)[1]
 public &#39;val&#39; => int 30
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40
 
object(A)[3]
 public &#39;val&#39; => int 20
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40

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Deep cloning: All attribute data of an object are completely copied. You need to use the magic method __clone(), and implement deep cloning in it

<?php
class B{
 public $val = 10;
}
class A{
 public $val = 20;
 public $b;
 public function __construct(){
  $this->b = new B();
 }
 public function __clone(){
  $this->b = clone $this->b;
 }
}
$obj_a = new A();
$obj_b = clone $obj_a;
$obj_a->val = 30;
$obj_a->b->val = 40;
var_dump($obj_a);
echo &#39;<br>&#39;;
var_dump($obj_b);

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The running results are as follows:

object(A)[1]
 public &#39;val&#39; => int 30
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40
 
object(A)[3]
 public &#39;val&#39; => int 20
 public &#39;b&#39; =>
 object(B)[4]
  public &#39;val&#39; => int 10

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I hope this article will be helpful to everyone in PHP programming.

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