PHP array function that returns a subset for given keys

This works:

function sub_array(array $haystack, array $needle){    return array_intersect_key($haystack, array_flip($needle));}$myArray = array(    'apple'=>'red',    'banana'=>'yellow',    'lettuce'=>'green',    'strawberry'=>'red',    'tomato'=>'red');$keys = array(    'lettuce',    'tomato');$ret = sub_array($myArray, $keys);var_dump($ret);

You can use array_intersect_key, but it uses second array with keys and values. It computes the intersection of arrays using keys for comparison

array_intersect_key

<?php$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'   => 8);$array3 = array('green' => '', 'blue' => '', 'yellow' => '', 'cyan' => '');$array4 = array('green', 'blue', 'yellow', 'cyan');var_dump(array_intersect_key($array1, $array2));var_dump(array_intersect_key($array1, $array3));var_dump(array_intersect_key($array1, $array4));?>

The above example will output:

array(2) {  ["blue"]=>  int(1)  ["green"]=>  int(3)}array(2) {  ["blue"]=>  int(1)  ["green"]=>  int(3)}array(0) {}

    $ret = array_filter($myArray, function ($key) use ($keys) {        return in_array($key, $keys);    }, ARRAY_FILTER_USE_KEY);