Laravel - 如何在验证中限制与“in”混合的数组大小？

Question

How to limit array size to have 2 items in it or 4. not min 2 and max 4.

$validity = Validator::make($data, [
    'array',
    // 'between:2,4', this will include 3 too. but I need only 2 and 4.
    // 'in:2,4' something like this
]);

Answer 1

You need a custom Rule, probably a Closure like following:

https://laravel.com/docs/7.x/validation#using-closures

function ($attribute, $value, $fail) {
    if (!in_array(count($value), [2, 4])) {
        $fail($attribute.' must have either 2 elements or 4.');
    }
}