In what scenarios would it be more efficient to use a custom function like array_differences instead of built-in PHP functions?

When dealing with arrays in PHP, there may be scenarios where built-in functions do not provide the specific functionality needed. In such cases, creating a custom function like array_differences can be more efficient and tailored to the specific requirements. For example, if you need to compare two arrays and find the elements that are present in one array but not in the other, a custom function can provide a straightforward solution.

function array_differences($array1, $array2) {
    return array_values(array_diff($array1, $array2));
}

$array1 = [1, 2, 3, 4, 5];
$array2 = [2, 3, 5];
$differences = array_differences($array1, $array2);

print_r($differences); // Output: [1, 4]