Question

$arr1 = array('potato'=>1,'tomato'=>2,'apple'=>5,'banana'=>10);
$arr2 = array('orange'=>20,'tomato'=>3,'apple'=>5,'banana'=>20);

I need function that would return array(‘tomato’,’banana’), consider that it omits keys that don’t exist in one or the other array. Apple has the same value in both arrays, so it should be omitted – returned should be only keys whose values differ and are set

Answer 1

This should work (demo):

$arr1 = array('potato'=>1,'tomato'=>2,'apple'=>5,'banana'=>10);
$arr2 = array('orange'=>20,'tomato'=>3,'apple'=>5,'banana'=>20);
$result = array_keys(array_diff(array_intersect_key($arr1, $arr2), $arr2));
print_r($result);

Output:

Array
(
    [0] => tomato
    [1] => banana
)

Reference:

• array_intersect_key — Computes the intersection of arrays using keys for comparison
• array_diff — Computes the difference of arrays
• array_keys — Return all the keys or a subset of the keys of an array