Laravel 从多维集合中压平和提取

我必须检索一个数组id从给定的集合中，类似[10,54,61,21等]。 我试过了flatten, pluck，但除了foreach这是我想在这一步删除的东西。

// Model
class Children extends Eloquent {
    public function directChildrens(){
        return $this->hasMany('App\Children','father_id','id')->select('id','father_id');
    }

    public function childrens(){
        return $this->directChildrens()->with('childrens');
    }
}

// Controller
return $children->childrens()->get();

正如预期的那样，它工作得很好。这是一个结果：

[{
"id": 10,
"father_id": 2,
"childrens": [
    {
        "id": 54,
        "father_id": 10,
        "childrens": [
            {
                "id": 61,
                "father_id": 54,
                "childrens": []
            }
        ]
    },
    {
        "id": 21,
        "father_id": 10,
        "childrens": []
    }
]
}]

我怎样才能执行拔取（'id'）这个集合以获得[10,54,61,21] ?

$result = [
            [
                "id" => 10,
                "father_id" => 2,
                "childrens" => [
                    [
                        "id" => 54,
                        "father_id" => 10,
                        "childrens" => [
                            [
                                "id" => 61,
                                "father_id" => 54,
                                "childrens" => []
                            ]
                        ]
                    ],
                    [
                        "id" => 21,
                        "father_id" => 10,
                        "childrens" => []
                    ]
                ]
            ]
        ];

return collect($result)
        ->map(function ($value) {
            return Arr::dot($value); // converts it to the dot notation version (added the example at the end)
        })
        ->collapse() // collapse them into a single one
        ->filter(function ($value, $key) {
            return $key === 'id' || Str::endsWith($key, '.id'); // filter first id + patterns of .id
        })
        ->values() // discard dot notation keys
        ->toArray();

Arr::dot()方法将集合转换为以下格式，将所有集合展平为同一级别。

[
  {
    "id": 10,
    "father_id": 2,
    "childrens.0.id": 54,
    "childrens.0.father_id": 10,
    "childrens.0.childrens.0.id": 61,
    "childrens.0.childrens.0.father_id": 54,
    "childrens.0.childrens.0.childrens": [],
    "childrens.1.id": 21,
    "childrens.1.father_id": 10,
    "childrens.1.childrens": []
  }
]

感谢 @Dan 关于已弃用/删除功能的警告array_dot。替换为Arr::dot()