I want to check if an array only contains allowed element values (are available in another array).
Example:
$allowedElements = array('apple', 'orange', 'pear', 'melon');
checkFunction(array('apple', 'orange'), $allowedElements); // OK
checkFunction(array('pear', 'melon', 'dog'), $allowedElements); // KO invalid array('dog') elements
What is the best way to implement this checkFunction($a, $b) function?
count($array) == count(array_intersect($array,$valid));
.. or come to think of it;
$array == array_intersect($array,$valid);
Note that this would yield true if (string)$elementtocheck=(string)$validelement, so in essence, only usable for scalars. If you have more complex values in your array (arrays, objects), this won't work. To make that work, we alter it a bit:
sort($array);//order matters for strict
sort($valid);
$array === array_intersect($valid,$array);
... assuming that the current order does not matter / sort() is allowed to be called.
You can use array_intersect() as suggested here. Here's a little function:
function CheckFunction($myArr, $allowedElements)
{
$check = count(array_intersect($myArr, $allowedElements)) == count($myArr);
if($check) {
return "Input array contains only allowed elements";
} else {
return "Input array contains invalid elements";
}
}
array_intersect?)If you are seeking a boolean result, PHP8.4's array_all() is a single call which also performs efficiently due to its conditional early return upon false evaluation. Demo
$allowedElements = ['apple', 'orange', 'pear', 'melon'];
$array = ['apple', 'orange'];
var_export(
array_all(
$array,
fn($v) => in_array($v, $allowedElements)
)
);
// true