Simple PHP Function to Whitelist Array Keys

A simple little PHP method for returning only the entries within an array that have array keys in a whitelist:-

/**
 * Returns only array entries listed in a whitelist
 *
 * @param array $array original array to operate on
 * @param array $whitelist keys you want to keep
 * @return array
 */
function arrayWhitelist($array, $whitelist) {
	return array_intersect_key(
		$array, 
		array_flip($whitelist)
	);	
}

To use you just need to pass the array you want to operate on and an array of keys that you want to keep (the whitelist):-

$data = array(
	'apple' => 'green', 
	'raspberry' => 'red', 
	'banana' => 'yellow'
);
$whitelist = array(
	'apple', 
	'banana'
);
print_r(arrayWhitelist($data, $whitelist));

This will output:-

Array
(
    [apple] => green
    [banana] => yellow
)