SplObjectStorage::getHash

    (PHP 5 >= 5.4.0, PHP 7, PHP 8)

    SplObjectStorage::getHash — Calculate a unique identifier for the contained objects

    说明

    publicSplObjectStorage::getHash(object$object): string

    This method calculates an identifier for the objects added to an SplObjectStorage object.

    The implementation in SplObjectStorage returns the same value as spl_object_hash().

    The storage object will never contain more than one object with the same identifier. As such, it can be used to implement a set (a collection of unique values) where the quality of an object being unique is determined by the value returned by this function being unique.

    参数

    object

    The object whose identifier is to be calculated.

    返回值

    A string with the calculated identifier.

    错误／异常

    A RuntimeException is thrown when the returned value is not a string.

    示例

    示例 #1 SplObjectStorage::getHash() example

    <?php
    class OneSpecimenPerClassStorage extends SplObjectStorage {
    public function     getHash($o) {
    return     get_class($o);
    }
    }
    class     A {}

    $s = new OneSpecimenPerClassStorage;
    $o1 = new stdClass;
    $o2 = new stdClass;
    $o3 = new A;

    $s[$o1] = 1;
    //$o2 is considered equal to $o1 so the value is replaced
    $s[$o2] = 2;
    $s[$o3] = 3;

    //these are considered equal to the objects before
    //so they can be used to access the values stored under them
    $p1 = new stdClass;
    $p2 = new A;
    echo     $s[$p1], "\n";
    echo     $s[$p2], "\n";
    ?>

    以上示例的输出类似于：

    2 3

    参见

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