Dark Corners Of The SPL - Dallas PHP July

PHP is a huge language, with lots of "kitchen sink" functionality for you to build data structures with. But did you know PHP includes a standard library that has built-in structures like linked lists, queues, stacks, and higher-performance arrays? This talk will cover a few of the more interesting ones in depth, including how to use them and most importantly why you'd use them over other solutions.

Transcript

1. Dark Corners of the SPL Photo By: SSG Ryan Boas
2. http://foto.wuestenigel.com/work-in-progress/
3. Photo By: Tom Walsh
4. Photo By: NASA Goddard Space Flight Center
5. Data Structures SplDoublyLinkedList SplStack SplQueue SplHeap SplMaxHeap SplMinHeap SplPriorityQueue SplFixedArray SplObjectStorage
6. Big-O O(1) - Constant no matter how big your data O(log n) - Grows slowly with your data O(n) - Grows linearly with your data O(n2) - Grows quadratically with your data O(2n) - Grows exponentially with your data O(n!) - LOL
7. Photo By: Cmglee
8. Data Structures SplDoublyLinkedList SplStack SplQueue SplPriorityQueue SplFixedArray SplObjectStorage SplHeap SplMaxHeap SplMinHeap
9. Image By: Bhavikp19
10. SplDoublyLinkedList Access: O(n) Search: O(n) Insert: O(1) Delete: O(1)
11. $list = new SplDoublyLinkedList(); $list->push('Ash'); $list->push('Bingo'); $list->push('Charlie'); $list->push('Echo'); foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL;
12. $list->push('Echo'); foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL; 0 Ash 1 Bingo 2 Charlie 3 Echo
13. 0 Ash 1 Bingo 2 Charlie 3 Echo $list->add(3, 'Delta'); foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL;
14. foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL; 0 Ash 1 Bingo 2 Charlie 3 Delta 4 Echo
15. 2 Charlie 3 Delta 4 Echo $list->rewind(); echo sprintf( "It's %s's turn! They take out %s!", $list->current(), $list[2] ), PHP_EOL; $list->offsetUnset(2); foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL;
16. foreach ($list as $key => $character) { echo $key, ' ', $character, PHP_EOL; } echo PHP_EOL; It's Ash's turn! They take out Charlie! 0 Ash 1 Bingo 2 Delta 3 Echo
17. Data Structures SplDoublyLinkedList SplStack SplQueue SplPriorityQueue SplFixedArray SplObjectStorage SplHeap SplMaxHeap SplMinHeap
18. Data Structures SplDoublyLinkedList SplStack SplQueue SplPriorityQueue SplFixedArray SplObjectStorage SplHeap SplMaxHeap SplMinHeap
19. Image By: Ermishin
20. SplHeap Access: O(log n) Search: O(log n) Insert: O(log n) Delete: O(log n)
21. class Character { public $name; public $initiative; public function __construct( string $name, int $init ) { $this->name = $name; $this->initiative = $init; } }
22. class InitiativeHeap extends SplMaxHeap { public function compare($a, $b) : int { return $a->initiative - $b->initiative; } }
23. $init = new InitiativeHeap(); $init->insert(new Character('Ash', random_int(1, 30))); $init->insert(new Character('Bingo', random_int(1, 30))); $init->insert(new Character('Charlie', random_int(1, 30))); $init->insert(new Character('Echo', random_int(1, 30))); foreach ($init as $character) { echo sprintf( '%s %d', $character->name, $character->initiative ), PHP_EOL; }
24. foreach ($init as $character) { echo sprintf( '%s %d', $character->name, $character->initiative ), PHP_EOL; } Ash 30 Echo 27 Charlie 16 Bingo 12
25. Data Structures SplDoublyLinkedList SplStack SplQueue SplHeap SplMaxHeap SplMinHeap SplPriorityQueue SplFixedArray SplObjectStorage
26. SplFixedArray Access: O(1) Search: O(n) Insert: O(1) or O(n) Delete: O(n)
27. $a = [ 'foo' => 1, 'bar' => new StdClass(), 1 => null, false => true, ]; var_dump($a); array(3) { [“foo"]=>int(1) [“bar"]=>object(stdClass)#1 (0) {} [1]=>NULL [0]=>bool(true) } $b = [ 0 => 10, 2 => 22, PHP_INT_MAX => PHP_INT_MAX, ]; var_dump($b); array(3) { [0]=>int(10) [2]=>int(22) [9223372036854775807]=> int(9223372036854775807) }
28. $c = new SplFixedArray(3); $c[0] = 10; $c[1] = 20; $c[2] = 42; var_dump($c); object(SplFixedArray)#2 (3) { [0]=>int(10) [1]=>int(20) [2]=>int(42) }
29. $d = new SplFixedArray(3); $d[0] = 10; $d[1] = 20; $d[2] = 42; $d[3] = 99; var_dump($d); PHP Fatal error: Uncaught RuntimeException: Index invalid or out of range in SplFixedArray.php:33 Stack trace: #0 {main} thrown in SplFixedArray.php on line 33
30. $e = new SplFixedArray(3); $e[0] = 10; $e[1] = 20; $e[2] = 42; $e->setSize(4); $e[3] = 99; var_dump($e); object(SplFixedArray)#5 (4) { [0]=>int(10) [1]=>int(20) [2]=>int(42) [3]=>int(99) }
31. Data Structures SplDoublyLinkedList SplStack SplQueue SplHeap SplMaxHeap SplMinHeap SplPriorityQueue SplFixedArray SplObjectStorage
32. Data Structures SplDoublyLinkedList SplStack SplQueue SplHeap SplMaxHeap SplMinHeap SplPriorityQueue SplFixedArray SplObjectStorage
33. $char = new Character(); $storage = []; $storage[$char] = new Character(); Warning: Illegal offset type in SplObjectStorage.php on line 3
34. class Character {} class Enemy {} class Buff {} class Ailment {}
35. class Buff {} class Ailment {} $fighter = new Character(); $mage = new Character(); $goblin = new Enemy(); $ogre = new Enemy(); $haste = new Buff(); $poison = new Ailment();
36. $encounter = new SplObjectStorage(); $encounter->attach($fighter, [$haste]); $encounter->attach($mage, [$haste, $poison]); $encounter[$goblin] = [$poison]; $encounter->attach($ogre); foreach ($encounter as $key => $value) { print_r($key); echo PHP_EOL; print_r($value); } $poison = new Ailment();
37. foreach ($encounter as $key => $value) { print_r($key); echo PHP_EOL; print_r($value); } 0 Character Object() 1 Character Object() 2 Enemy Object() 3 Enemy Object()
38. object(SplObjectStorage)#7 (1) { ["storage":"SplObjectStorage":private]=>array(4) { ["000000005460553e00000000545bda63"]=>array(2) { ["obj"]=>object(Character)#1 (0) {} ["inf"]=>array(1) { [0]=>object(Buff)#5 (0) {} } } } }
39. foreach ($encounter as $key) { print_r($key); print_r($encounter[$key]); }
40. print_r($encounter[$key]); } Character Object() // fighter Array( [0] => Buff Object() // haste ) Character Object() // mage Array( [0] => Buff Object() // haste [1] => Ailment Object() // poison ) Enemy Object() // golbin Array( [0] => Ailment Object() // poison ) Enemy Object()
41. –Lady Gaga “I just am committed wholeheartedly to theatre with no intermission.”
42. SPL Interfaces Countable OuterIterator RecursiveIterator SeekableIterator SplObserver SplSubject
43. Countable interface Countable { public function count() : int; }
44. class Countable { public function count() : int { return 42; } } $foo = new Countable(); echo count($foo), PHP_EOL;
45. class Countable { public function count() : int { return 42; } } $foo = new Countable(); echo count($foo), PHP_EOL; Warning: count(): Parameter must be an array or an object that implements Countable in Countable.php on line 13 1
46. object that implements Countable in Countable.php on line 13 1 class ActuallyCountable implements Countable { public function count() { return 42; } } $bar = new ActuallyCountable(); echo count($bar), PHP_EOL;
47. SplSubject interface SplSubject { function attach(SplObserver $observer): void; function detach(SplObserver $observer): void; function notify(): void; }
48. SplObserver interface SplObserver { function update(SplSubject $subject): void; }
49. https://speakerdeck.com/omnicolor/dark-corners-of-the-spl https://joind.in/ https://twitter.com/omnicolor Omni Adams omni@digitaldarkness.com