Select a subset of an associative array by providing the keys.

array_select.php

<?php
/**
 * Select a subset of an associative array by providing the keys.
 *
 * @param array $assoc
 * @param array $keys
 * @return array
 */
function array_select(array $assoc, array $keys) {
    return array_intersect_key($assoc, array_flip($keys));
}