php 重载等于运算符

发布于 2024-10-16 18:59:40 字数 663 浏览 5 评论 0原文

在 PHP 程序中，我有一个包含一些自定义对象的数组，我想查找该数组是否包含某个对象。当然，我可以使用 array_search，但这会检查对象是否是同一对象，而不是它是否具有相同的变量。所以我希望能够为对象创建自己的比较函数，我可以将其与 array_search 方法（或类似的方法）一起使用。我希望能够做这样的事情：

class foo
{
    public $_a,$_b;
    function __construct($a,$b)
    {
        $this->_a = $a;
        $this->_b = $b;
    }

    function __equals($object)
    {
        return $this->_a == $object->_a;
    }
}
$f1 = new foo(5,4);
$f2 = new foo(4,6);
$f3 = new foo(4,5);

$array = array($f1,$f2);
$idx = array_search($f3,$array); // return 0

这样的事情可能吗？我知道我也可以创建自己的 array_search 方法，该方法使用类中的方法，但是我必须使用 2 个不同的搜索函数，一个用于具有自己的比较函数的类，另一个用于那些没有自己的比较函数的类t。

原文

In a PHP program I have an array of some custom objects, and I want to find if the array contains a certain object. Of course I can use array_search, but this checks if the objects are the same object, not if it has the same variables. So I want to be able to create my own compare function for the objects, which I can use with the array_search method (or something similar).
I want to be able to do something like this:

class foo
{
    public $_a,$_b;
    function __construct($a,$b)
    {
        $this->_a = $a;
        $this->_b = $b;
    }

    function __equals($object)
    {
        return $this->_a == $object->_a;
    }
}
$f1 = new foo(5,4);
$f2 = new foo(4,6);
$f3 = new foo(4,5);

$array = array($f1,$f2);
$idx = array_search($f3,$array); // return 0

Is something like this possible?
I know I can also create my own array_search method which uses a method from the class, but than I'd have to use 2 different search functions, one for the classes which do have their own compare function, and one for those which haven't.

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

七分※倦醒 2024-10-23 18:59:40

这是我最近发现的一个巧妙的小技巧：

class Foo {
    public $a;
    public $b;

    public function __toString() {
        return (string)$this->a;
    }

    public function __construct($a, $b) {
         $this->a = $a;
         $this->b = $b;
    }

}

$a = new Foo(1, 'a');
$b = new Foo(2, 'b');
$c = new Foo(3, 'c');
$d = new Foo(2, 'd');
$array = array($a, $b);

$key = array_search($d, $array);         // false

$key = array_search((string)$c, $array); // false
$key = array_search((string)$d, $array); // 1

这也有效：

$is_equal = ((string)$d == $b);          // true

当传递字符串 $needle 时，array_search 将尝试转换 $haystack< 中包含的对象/em> 到字符串进行比较，方法是调用 __toString 魔术方法（如果存在），在本例中返回 Foo::$a。

Here's a neat little trick I recently found out:

class Foo {
    public $a;
    public $b;

    public function __toString() {
        return (string)$this->a;
    }

    public function __construct($a, $b) {
         $this->a = $a;
         $this->b = $b;
    }

}

$a = new Foo(1, 'a');
$b = new Foo(2, 'b');
$c = new Foo(3, 'c');
$d = new Foo(2, 'd');
$array = array($a, $b);

$key = array_search($d, $array);         // false

$key = array_search((string)$c, $array); // false
$key = array_search((string)$d, $array); // 1

This also works:

$is_equal = ((string)$d == $b);          // true

When passed a string $needle, array_search will try to cast the objects contained in $haystack to string to compare them, by calling the __toString magic method if it exists, which in this case returns Foo::$a.

回复收藏 0 原文