如何安全地检索此对象的此属性？

Question

I have a Stripe subscription object that looks like this...

subscription: {
    items: {
        data: [
            plan: {
                id: 'my_plan_id'
            }
        ]
    }
}

What's the best way to safely retrieve the plan id? Currently I am doing the following.

'plan_id' => $subscription->items->data[0]->plan->id,

But, it looks like that will fail if items , data[0] , or plan , is not set. I could do nest if statements like, if (isset($subscription->items) && isset(data[0]) ... , but I am not sure that is the best way.

Is there a PHP method or Laravel method that I can use to extract that property safely that would be cleaner than that?

Answer 1

If you're using PHP 7+, you can use the null coalesce operator:

'plan_id' => $subscription->items->data[0]->plan->id ?? $default,

This will evaluate the value if it's available, otherwise it will use the default, without generating any warnings or errors.

Example:

$foo = new stdClass();
var_dump($foo->bar->baz->data[0]->plan->id ?? null);

Output:

NULL

Answer 2

您可以在整个选择器上使用isset函数：

isset($subscription->items->data[0]->plan->id) ? $subscription->items->data[0]->plan->id : null;

Answer 3

A rather cumbersome but generic method to access nested structures by a list of keys; can be made into a reusable function easily:

$id = array_reduce(['items', 'data', 0, 'plan', 'id'], function ($o, $k) {
    if (!$o) {
        return null;
    } else if (is_array($o) && isset($o[$k])) {
        return $o[$k];
    } else if (isset($o->$k)) {
        return $o->$k;
    }
}, $subscription);

Answer 4

you can take help of ternary condition to check if the value is set or not. If set then put that value otherwise put default as

$id=isset($subscription->items->data[0]->plan->id) ? $subscription->items->data[0]->plan->id : $your_dafault_value;

If the value is set then the $id looks like

$id='my_plan_id';//In most cases we should consider null as a default value

If the value is not set then the $id looks liks

 $id='your_dafault_value';