如何在php中使用required_if Laravel验证

I want to give validation if weight is not empty then shipping_cost required and vise verse.

array('weight' => 'numeric|required_if:shipping_cost,value',
'shipping_cost' => 'numeric|required_if:weight,value')

What will be the value for 'weight,value' and 'shipping_cost,value' ?

I am not sure you can use the required_if without a specific value.

You can use a condition for that.

$rules = [
    'weight' => ['numeric'],
    'shipping_cost' => ['numeric']
]

// Shipping costs requires weight, and weight requires shipping cost
if ( ! empty(Input::get('weight')) or ! empty(Input::get('shipping_cost')))
{
    $weight['shipping_cost'][] = 'required';
    $rules['weight'][] = 'required';
}