php-ml/src/Math/Set.php

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<?php
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declare(strict_types=1);
namespace Phpml\Math;
use ArrayIterator;
use IteratorAggregate;
class Set implements IteratorAggregate
{
/**
* @var string[]|int[]|float[]|bool[]
*/
private $elements = [];
/**
* @param string[]|int[]|float[]|bool[] $elements
*/
public function __construct(array $elements = [])
{
$this->elements = self::sanitize($elements);
}
/**
* Creates the union of A and B.
*/
public static function union(self $a, self $b): self
{
return new self(array_merge($a->toArray(), $b->toArray()));
}
/**
* Creates the intersection of A and B.
*/
public static function intersection(self $a, self $b): self
{
return new self(array_intersect($a->toArray(), $b->toArray()));
}
/**
* Creates the difference of A and B.
*/
public static function difference(self $a, self $b): self
{
return new self(array_diff($a->toArray(), $b->toArray()));
}
/**
* Creates the Cartesian product of A and B.
*
* @return Set[]
*/
public static function cartesian(self $a, self $b): array
{
$cartesian = [];
foreach ($a as $multiplier) {
foreach ($b as $multiplicand) {
$cartesian[] = new self(array_merge([$multiplicand], [$multiplier]));
}
}
return $cartesian;
}
/**
* Creates the power set of A.
*
* @return Set[]
*/
public static function power(self $a): array
{
$power = [new self()];
foreach ($a as $multiplicand) {
foreach ($power as $multiplier) {
$power[] = new self(array_merge([$multiplicand], $multiplier->toArray()));
}
}
return $power;
}
/**
* @param string|int|float|bool $element
*/
public function add($element): self
{
return $this->addAll([$element]);
}
/**
* @param string[]|int[]|float[]|bool[] $elements
*/
public function addAll(array $elements): self
{
$this->elements = self::sanitize(array_merge($this->elements, $elements));
return $this;
}
/**
* @param string|int|float $element
*/
public function remove($element): self
{
return $this->removeAll([$element]);
}
/**
* @param string[]|int[]|float[] $elements
*/
public function removeAll(array $elements): self
{
$this->elements = self::sanitize(array_diff($this->elements, $elements));
return $this;
}
/**
* @param string|int|float $element
*/
public function contains($element): bool
{
return $this->containsAll([$element]);
}
/**
* @param string[]|int[]|float[] $elements
*/
public function containsAll(array $elements): bool
{
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return count(array_diff($elements, $this->elements)) === 0;
}
/**
* @return string[]|int[]|float[]|bool[]
*/
public function toArray(): array
{
return $this->elements;
}
public function getIterator(): ArrayIterator
{
return new ArrayIterator($this->elements);
}
public function isEmpty(): bool
{
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return $this->cardinality() === 0;
}
public function cardinality(): int
{
return count($this->elements);
}
/**
* Removes duplicates and rewrites index.
*
* @param string[]|int[]|float[]|bool[] $elements
*
* @return string[]|int[]|float[]|bool[]
*/
private static function sanitize(array $elements): array
{
sort($elements, SORT_ASC);
return array_values(array_unique($elements, SORT_ASC));
}
}