diffKeys 方法和另外一个集合或 PHP 数组的键（keys）进行比较，然后返回原集合中存在而指定集合中不存在键所对应的键 / 值对：

$collection = collect([
    'one' => 10,
    'two' => 20,
    'three' => 30,
    'four' => 40,
    'five' => 50,
]);

$diff = $collection->diffKeys([
    'two' => 2,
    'four' => 4,
    'six' => 6,
    'eight' => 8,
]);

$diff->all();

// ['one' => 10, 'three' => 30, 'five' => 50]Copy