README

PHP lightweight hashtable (associative array) wrapper for Set data structures.

Sets are effectively containers that hold unique values.

Excogitation

What is 'unique'?

Unique is determined by this package via a hashed value for any given input. The hash value is generated internally for continuity. The hashed value is then used as a way to identify a hashtables element/value

Why create an internal hash code? Why not use built-in spl_object_hash or hash

There are many reasons why not to rely on these values, but fundamentally, they don't guarantee uniqueness.

Take for example:

$aStd = new stdClass;
$aStd->foo = "foobar";

$bStd = new stdClass;
$bStd->foo = "foobar";

The two objects are considered equal because they have the same amount of properties, the properties value's are identical and they both are derived stdClass objects.

However, the result of the 2 hashes:

var_dump(spl_object_hash($aStd)); //00000000000000010000000000000000
var_dump(spl_object_hash($bStd)); //00000000000000020000000000000000

Additionally spl_object_hash only allows objects and hash|md5 etc expect strings, not all objects include __toString() logic.

In short, this is a very complex problem to solve because uniqueness is never not guaranteed, but the hash can and should limit potential collisions which the package strives for

Installation

composer require ft/sets

Set Classes

Set

A container that can hold zero to many elements of any data type

classDiagram
    class Countable {
        <<interface>>
        public count(): int
    }
    class Traversable {
        <<interface>>
    }
    class Iterator {
        <<interface>>
        public rewind(): void
        public current(): mixed
        public key(): mixed
        public next(): void
        public valid(): bool
    }
    Countable <|-- Set
    Traversable <|-- Set
    Iterator <|-- Set
    class Set {
        __construct(array $elements =[], bool $silently_ignore_null = false)
        add(mixed $element): bool
        addAll(array $array)
        remove(mixed $element) : bool
        removeAll(array $array)
        clear()
        indexOf(array|string|int|float|bool|Comparable $value): int
        union(Set $b): Set
        intersection(Set $b): Set
        difference(Set $b): Set
        subset(Set $b): bool
        pop(): mixed
        shift(): mixed
        last(): mixed
        first(): mixed
        isEmpty(): bool
        size(): int
        equals(Set $b): bool
        contains(mixed $element): bool
        filter(callable|SetPredicate $predicate): Set
        anyMatch(callable|SetPredicate $predicate): bool
        allMatch(callable|SetPredicate $predicate): bool
        noneMatch(callable|SetPredicate $predicate): bool
        choose(int $quantity): mixed
        levenshtein(string $query): ?string
        toArray(array $keys = []): array
        map(callable $callable) : Set
        flatten(int $depth = 1): Set
    }

StrictSet

A subclass of Set, which only permits the same data type to exist in a given instance

Note The first element added to a StrictSet dictates what type of elements can be added subsequently

When a StrictSet element is added that is not the same type an InvalidArgumentException will be thrown. Subclasses of an element are not even permitted

SortedSet

A sorted set is one which the values are sorted in ascending order, or descending if elected. Therefore sorted sets must contain the same elements (a la StrictSet)

Additional functions are provided for numerical data types

Warning There is no locale integration for string comparisons, that's beyond the scope of this library

classDiagram
    class Set
    class StrictSet
    Set --|> StrictSet
    StrictSet --|> SortedSet
    class SortedSet {
        partition(int $offset, ?int $length = null): SortedSet
        ceiling(string|int|float $value): string | int | float | null
        floor(string|int|float $value): string | int | float | null
        higher(string|int|float $value): string | int | float | null
        lower(string|int|float $value): string | int | float | null
        headSet(string|int|float $value): string | int | float | null
        tailSet(string|int|float $value): string | int | float | null
        reverse(string|int|float $value): string | int | float | null
    }

Examples

Set

$car = new stdClass;
$car->make = 'toyota';

$set = new Set;
$set->add(1);
$set->add(2.);
$set->add('foobar');
$set->add('foobar');
$set->add(new stdClass);
$set->add(new stdClass);
$set->add(true);
$set->add(true === true);
$set->add($car);

var_dump($set->toArray());
/*
array(4) {
  [0] => int(1)
  [1] => double(2)
  [2] => string(6) "foobar"
  [3] => class stdClass#2 (0) { }
  [4] => class stdClass#3 (1) {
    public $make => string (6) "toyota"
  }
}
*/

SortedSet

$set = new SortedSet;

$set->addAll([
    'pea',
    'pineapple',
    'apple',
    'apple',
    'orange',
    'apple',
    'banana',
    'potato',
    'radish',
    'carrot',
    'pea',
    'apple',
    'pea',
    'bean'
]);

var_dump($set->toArray());
/*
array(9) {
  [0] => string(5) "apple"
  [1] => string(6) "banana"
  [2] => string(4) "bean"
  [3] => string(6) "carrot"
  [4] => string(6) "orange"
  [5] => string(3) "pea"
  [6] => string(9) "pineapple"
  [7] => string(6) "potato"
  [8] => string(6) "radish"
}
*/