laravel将级联数组通过f_id转变成正常数组

可以使用 Laravel 中的 `Collection` 类来将级联数组转换成正常数组。假设你有以下的级联数组：

$data = [
    [
        'id' => 1,
        'name' => 'A',
        'f_id' => 0,
        'children' => [
            [
                'id' => 2,
                'name' => 'B',
                'f_id' => 1,
                'children' => [
                    [
                        'id' => 3,
                        'name' => 'C',
                        'f_id' => 2,
                        'children' => []
                    ]
                ]
            ]
        ]
    ],
    [
        'id' => 4,
        'name' => 'D',
        'f_id' => 0,
        'children' => []
    ]
];

可以使用以下代码将其转换成正常数组：

$collection = collect($data);

$normalized = $collection->flatMap(function ($item) {
    return array_merge($item, ['children' => $item['children'] ? $item['children']->pluck('id')->toArray() : []]);
})->toArray();

这段代码会将每个子数组中的 `children` 转换成子数组中 `id` 的数组。转换后的结果如下：

[
    [
        'id' => 1,
        'name' => 'A',
        'f_id' => 0,
        'children' => [2, 3]
    ],
    [
        'id' => 2,
        'name' => 'B',
        'f_id' => 1,
        'children' => [3]
    ],
    [
        'id' => 3,
        'name' => 'C',
        'f_id' => 2,
        'children' => []
    ],
    [
        'id' => 4,
        'name' => 'D',
        'f_id' => 0,
        'children' => []
    ]
]