SplObjectStorage::getHash
(PHP 5 >= 5.4.0, PHP 7, PHP 8)
SplObjectStorage::getHash —
Calculate a unique identifier for the contained objects
Description
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.
Parameters
object
-
The object whose identifier is to be calculated.
Return Values
A string with the calculated identifier.
Examples
Example #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";
?>
The above example will output
something similar to: