Merging two multi dimensional arrays, overwriting existing values

array_merge_recursive_distinct.php

<?php

/**
 * array_merge_recursive does indeed merge arrays, but it converts values with duplicate
 * keys to arrays rather than overwriting the value in the first array with the duplicate
 * value in the second array, as array_merge does. I.e., with array_merge_recursive,
 * this happens (documented behavior):
 *
 * array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
 *     => array('key' => array('org value', 'new value'));
 *
 * array_merge_recursive_distinct does not change the datatypes of the values in the arrays.
 * Matching keys' values in the second array overwrite those in the first array, as is the
 * case with array_merge, i.e.:
 *
 * array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value'));
 *     => array('key' => array('new value'));
 *
 * Parameters are passed by reference, though only for performance reasons. They're not
 * altered by this function.
 *
 * @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk>
 * @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com>
 *
 * @param array $array1
 * @param array $array2
 *
 * @return array
 */
protected function array_merge_recursive_distinct(array &$array1, array &$array2)
{
    $merged = $array1;

    foreach ($array2 as $key => &$value) {
        if (is_array($value) && isset($merged[$key]) && is_array($merged[$key])) {
            $merged[$key] = $this->array_merge_recursive_distinct($merged[$key], $value);
        } else {
            $merged[$key] = $value;
        }
    }

    return $merged;
}

?>