Set
The Set class mimics the behavior of the JavaScript Set object in PHP. It allows you to store unique values of any type—scalars, arrays, or objects—while automatically filtering duplicates and maintaining the order in which items were added.
Concept & Generics
A Set is fundamentally different from a standard array because it enforces uniqueness. If you try to add the same value twice, the second attempt is ignored.
Type Safety
The class supports PHPDoc templates (@template T), enabling static analysis tools to enforce strict typing.
$names = new Set();
API Reference
Modification
add(T $value): void
Adds a value. If the value already exists, no action is taken.
delete(T $value): void
Removes the specified value from the collection.
clear(): void
Wipes all values from the set, resetting size to 0.
Inspection
has(T $value): bool
Checks for existence.
values(): T[]
Returns a standard indexed array of all items.
size(): int
Returns the count of items.
How Uniqueness Works
The class uses a private getKey($value) method to fingerprint values:
- Scalars (strings/ints): Used directly as the key.
- Objects: Fingerprinted using
spl_object_id(checks instance identity). - Arrays: Fingerprinted using
md5(serialize($value))(checks deep equality).
Usage Examples
Basic Scalar Usage
<?php
use PP\Set;
$tags = new Set();
$tags->add('php');
$tags->add('javascript');
$tags->add('php'); // Ignored
echo $tags->size(); // Output: 2
?>Working with Objects
<?php
use PP\Set;
$userA = new stdClass();
$userA->name = 'John';
$userB = new stdClass();
$userB->name = 'Jane';
$activeUsers = new Set();
$activeUsers->add($userA);
$activeUsers->add($userB);
$activeUsers->add($userA); // Ignored: Same instance
// However, a new object with same data is distinct:
$userC = new stdClass();
$userC->name = 'John';
$activeUsers->add($userC); // Added: Different instance ID
?>