Laravel - 如何限制验证中混合使用"in"的数组大小？

Question

如何将数组大小限制为包含2项或4项。而不是最小值2和最大值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

您需要一个自定义规则，可能是类似以下的闭包：

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

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