## diffKeys方法 与另外一个集合或 PHP 数组的「键」进行比较，然后返回原集合中存在而给定的集合中不存在「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] ~~~