SorensenDiceCoefficient.php
No OneTemporary
Actions

Size

1 KB

Referenced Files

None

Subscribers

None

SorensenDiceCoefficient.php
View Options

	<?php
	declare(strict_types=1);

	namespace Keruald\OmniTools\Strings;

	use Keruald\OmniTools\Strings\Multibyte\OmniString;

	/**
	* Computes the Sørensen–Dice coefficient, a statistic used to evaluate
	* the similarity between two strings.
	*/
	class SorensenDiceCoefficient {

	/**
	* @var string[]
	*/
	private array $x;

	/**
	* @var string[]
	*/
	private array $y;

	///
	/// Constructors
	///

	/**
	* @param string $left The first string to compare
	* @param string $right The second string to compare
	*/
	public function __construct (string $left, string $right) {
	$this->x = (new OmniString($left))->getBigrams();
	$this->y = (new OmniString($right))->getBigrams();
	}

	/**
	* Allows to directly compute the coefficient between two strings.
	*
	* @param string $left The first string to compare
	* @param string $right The second string to compare
	*
	* @return float The Sørensen–Dice coefficient for the two specified strings.
	*/
	public static function computeFor(string $left, string $right) : float {
	$instance = new self($left, $right);

	return $instance->compute();
	}

	///
	/// Sørensen formula
	///

	/**
	* @return float The Sørensen–Dice coefficient.
	*/
	public function compute() : float {
	return 2 * $this->countIntersect()
	/
	$this->countCharacters();
	}

	private function countIntersect () : int {
	$intersect = array_intersect($this->x, $this->y);

	return count($intersect);
	}

	private function countCharacters () : int {
	return count($this->x) + count($this->y);
	}

	}