PHP中对象的不同集合

spl_object_hash 将帮助您确定两个对象是否相同。

由于php5.2,有一个本机对象集合 SplObjectStorage :

splObjectStorage类提供从对象到数据或忽略数据的对象集的映射。这种双重目的在许多情况下都是有用的,包括需要唯一地标识对象。

例子

$obj1 = new StdClass; $obj1->prop = 1;
$obj2 = new StdClass; $obj2->prop = 2;
$obj3 = new StdClass; $obj3->prop = 3;
$obj4 = new StdClass; $obj4->prop = 4;
$obj5 = new StdClass; $obj5->prop = 5;

$collection1 = new SplObjectStorage;
$collection1->attach($obj1);
$collection1->attach($obj2);
$collection1->attach($obj3);

$collection2 = new SplObjectStorage;
$collection2->attach($obj3);
$collection2->attach($obj4);
$collection2->attach($obj5);   

splObjectStorage实现了countable、iterator、traversable、serializable和arrayaccess(从5.3开始),因此您可以像迭代任何其他可遍历的一样轻松地对其进行迭代。同一对象用作对象集时,不能在SPlObjectStorage中出现两次。您可以使用以下函数轻松比较两个集合:

function collection_diff(SplObjectStorage $c1, SplObjectStorage $c2)
{
    $diff = new SplObjectStorage;
    foreach($c1 as $o) {
        if(!$c2->contains($o)) {
            $diff->attach($o);
        }
    }
    return $diff;
}

当然,您可以调整它以使用自定义比较。用法很简单:

$diff = collection_diff($collection1, $collection2);
var_dump( $diff ); // will contain $obj1 and $obj2

进一步阅读:

• http://www.colder.ch/news/01-08-2009/34/splobjectstorage-for-a-fa.html
• http://technosophos.com/content/set-objects-php-arrays-vs-splobjectstorage
• http://eide.org/2008/07/21/splobjectstorage/
• http://isc.sans.edu/diary.html?storyid=9133 (安全相关)