app/bundles/CoreBundle/Helper/ArrayHelper.php

<?php

namespace Mautic\CoreBundle\Helper;

/**
 * Helper functions for simpler operations with arrays.
 */
class ArrayHelper
{
    /**
     * If the $key exists in the $origin array then it will return its value.
     *
     * @param mixed $key
     * @param mixed $defaultValue
     *
     * @return mixed
     */
    public static function getValue($key, array $origin, $defaultValue = null)
    {
        return array_key_exists($key, $origin) ? $origin[$key] : $defaultValue;
    }

    /**
     * If the $key exists in the $origin array then it will return its value
     * and unsets the $key from the $array.
     *
     * @param mixed $key
     * @param mixed $defaultValue
     *
     * @return mixed
     */
    public static function pickValue($key, array &$origin, $defaultValue = null)
    {
        $value = self::getValue($key, $origin, $defaultValue);

        unset($origin[$key]);

        return $value;
    }

    /**
     * Selects keys defined in the $keys array and returns array that contains only those.
     */
    public static function select(array $keys, array $origin): array
    {
        return array_filter($origin, fn ($value, $key): bool => in_array($key, $keys, true), ARRAY_FILTER_USE_BOTH);
    }

    /**
     * Sum between two array.
     *
     * @param mixed[] $a1
     * @param mixed[] $b2
     *
     * @return mixed[]
     */
    public static function sum(array $a1, array $b2): array
    {
        return self::sumOrSub($a1, $b2);
    }

    /**
     * SUBSTRACT between two array.
     */
    public static function sub(array $a1, array $b2): array
    {
        return self::sumOrSub($a1, $b2, true);
    }

    /**
     * Removes null and empty string values from the array.
     *
     * @param mixed[] $array
     *
     * @return mixed[]
     */
    public static function removeEmptyValues(array $array): array
    {
        return array_filter(
            $array,
            fn ($value): bool => !is_null($value) && '' !== $value
        );
    }

    /**
     * Flip array or sub arrays.
     *
     * @param array<int|string|array<int|string>> $masterArrays
     *
     * @return array<int|string|array<int|string>>
     */
    public static function flipArray(array $masterArrays): array
    {
        if (!is_array(end($masterArrays))) {
            return array_flip($masterArrays);
        }

        return array_map(
            fn (array $subArray) => array_flip($subArray),
            $masterArrays
        );
    }

    /**
     * @param array<mixed> $multidimensionalArray
     *
     * @return array<mixed>
     */
    public static function flatten(array $multidimensionalArray): array
    {
        $flattenedArray = [];

        array_walk_recursive(
            $multidimensionalArray,
            function ($value, $key) use (&$flattenedArray): void {
                $flattenedArray[$key] = $value;
            }
        );

        return $flattenedArray;
    }

    /**
     *  SUM/SUBSTRACT between two arrays.
     *
     * @param bool $subtracted
     */
    private static function sumOrSub(array $a1, array $b2, $subtracted = false): array
    {
        return array_map(function ($x, $y) use ($subtracted) {
            if ($subtracted) {
                return $x - $y;
            } else {
                return $x + $y;
            }
        }, $a1, $b2);
    }
}