Automattic\WooCommerce\Vendor\Pelago\Emogrifier\Utilities

ArrayIntersector{} │ final │ WC 1.0

When computing many array intersections using the same array, it is more efficient to use array_flip() first and then array_intersect_key(), than array_intersect(). See the discussion at Stack Overflow for more information.

Of course, this is only possible if the arrays contain integer or string values, and either don't contain duplicates, or that fact that duplicates will be removed does not matter.

This class takes care of the detail.

No Hooks.

Usage

$ArrayIntersector = new ArrayIntersector();
// use class methods

Methods

1. public __construct(array $array)
2. public intersectWith(array $array)

ArrayIntersector{} ArrayIntersector{} code ^{WC 10.4.3}

final class ArrayIntersector
{
    /**
     * the array with which the object was constructed, with all its keys exchanged with their associated values
     *
     * @var array<array-key, array-key>
     */
    private $invertedArray;

    /**
     * Constructs the object with the array that will be reused for many intersection computations.
     *
     * @param array<array-key, array-key> $array
     */
    public function __construct(array $array)
    {
        $this->invertedArray = \array_flip($array);
    }

    /**
     * Computes the intersection of `$array` and the array with which this object was constructed.
     *
     * @param array<array-key, array-key> $array
     *
     * @return array<array-key, array-key>
     *         Returns an array containing all of the values in `$array` whose values exist in the array
     *         with which this object was constructed.  Note that keys are preserved, order is maintained, but
     *         duplicates are removed.
     */
    public function intersectWith(array $array): array
    {
        $invertedArray = \array_flip($array);

        $invertedIntersection = \array_intersect_key($invertedArray, $this->invertedArray);

        return \array_flip($invertedIntersection);
    }
}