PHP无限级分类代码问题

自己试着写了个无限级分类的，结果有些问题，想了很长时间了，感觉代码没问题呀，可就是结果不正确。现在整个人都懵了....

网上的栗子看了些，貌似写法跟我的不一样。

---

数组结构如下:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => 代码
            [parent] => 0
        )

    [1] => Array
        (
            [id] => 3
            [name] => 动漫
            [parent] => 0
        )

    [2] => Array
        (
            [id] => 4
            [name] => 治愈
            [parent] => 3
        )

    [3] => Array
        (
            [id] => 5
            [name] => 励志
            [parent] => 3
        )

    [4] => Array
        (
            [id] => 6
            [name] => 机战
            [parent] => 3
        )

    [5] => Array
        (
            [id] => 7
            [name] => 百合
            [parent] => 3
        )

    [6] => Array
        (
            [id] => 8
            [name] => 资源
            [parent] => 0
        )

    [7] => Array
        (
            [id] => 9
            [name] => app
            [parent] => 8
        )

    [8] => Array
        (
            [id] => 10
            [name] => 软件
            [parent] => 8
        )

    [9] => Array
        (
            [id] => 11
            [name] => 黑科技
            [parent] => 8
        )

)

其中 id 为分类唯一ID, parent 为父类ID
我写的代码 如下:

    function all($id=0){

            static $_class = null;

            if(is_null($_class))
                    $_class = select();  //这个得出来的就是以上的数组结构，然后赋值给了`$_class`变量

            $result = array();
            foreach($_class as $k => $v){
                    if($v['parent'] == $id){
                            unset($_class[$k]);
                            $v = array_merge($v, $this->all($v['id']));
                            $result['child'][] = $v;
                    }
            }

            return $result;

    }

    print_r(all(0));

回复内容：

自己试着写了个无限级分类的，结果有些问题，想了很长时间了，感觉代码没问题呀，可就是结果不正确。现在整个人都懵了....

网上的栗子看了些，貌似写法跟我的不一样。

---

数组结构如下:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => 代码
            [parent] => 0
        )

    [1] => Array
        (
            [id] => 3
            [name] => 动漫
            [parent] => 0
        )

    [2] => Array
        (
            [id] => 4
            [name] => 治愈
            [parent] => 3
        )

    [3] => Array
        (
            [id] => 5
            [name] => 励志
            [parent] => 3
        )

    [4] => Array
        (
            [id] => 6
            [name] => 机战
            [parent] => 3
        )

    [5] => Array
        (
            [id] => 7
            [name] => 百合
            [parent] => 3
        )

    [6] => Array
        (
            [id] => 8
            [name] => 资源
            [parent] => 0
        )

    [7] => Array
        (
            [id] => 9
            [name] => app
            [parent] => 8
        )

    [8] => Array
        (
            [id] => 10
            [name] => 软件
            [parent] => 8
        )

    [9] => Array
        (
            [id] => 11
            [name] => 黑科技
            [parent] => 8
        )

)

其中 id 为分类唯一ID, parent 为父类ID
我写的代码 如下:

    function all($id=0){

            static $_class = null;

            if(is_null($_class))
                    $_class = select();  //这个得出来的就是以上的数组结构，然后赋值给了`$_class`变量

            $result = array();
            foreach($_class as $k => $v){
                    if($v['parent'] == $id){
                            unset($_class[$k]);
                            $v = array_merge($v, $this->all($v['id']));
                            $result['child'][] = $v;
                    }
            }

            return $result;

    }

    print_r(all(0));

unset($_class[$k]);
这一行去掉

鉴于你这个还是用的递归来完成的，我这里提供2个方法，一个是递归的，一个是指针形态的。

第二个可能您暂时无法理解，但是为帮助您学习，以及方便到他人，以下是代码：

使用递归

// 呃，我真不忍心写出这个循环那么多遍的代码，求神解救我。

function _data_to_tree(&$items, $topid = 0, $with_id = TRUE)
{
    $result = [];
    foreach($items as $v)
        if ($topid == $v['parent'])  {
            $r = $v + ['children' => _data_to_tree($items, $v['id'], $with_id)];
            if ($with_id)
                $result[$v['id']] = $r;
            else
                $result[] = $r;
        }
            
    return $result;
}

使用PHP的指针特性

function _data_to_tree($items, $topid = 0, $with_id = TRUE)
{
    if ($with_id)
        foreach ($items as $item)
            $items[ $item['parent'] ]['children'][ $item['id'] ] = &$items[ $item['id'] ];
    else
        foreach ($items as $item)
                $items[ $item['parent'] ]['children'][] = &$items[ $item['id'] ];

         return isset($items[ $topid ]['children']) ? $items[ $topid ][ 'children' ] : [];
}

使用

传入你的上述数组，比如最顶层的ID为0

$data = [
   ['id' => 4, 'parent' => 1 , 'text' => 'Parent1'], 
   ['id' => 1, 'parent' => 0 , 'text' => 'Root'],
   ['id' => 2, 'parent' => 1 , 'text' => 'Parent2'], 
   ['id' => 3, 'parent' => 2 , 'text' => 'Sub1'], 
];
print_r ( _data_to_tree($data, 0) );

结果

Array
(
    [1] => Array
        (
            [id] => 1
            [parent] => 0
            [text] => Root
            [children] => Array
                (
                    [4] => Array
                        (
                            [id] => 4
                            [parent] => 1
                            [text] => Parent1
                            [children] => Array
                                (
                                )
                        )
                    [2] => Array
                        (
                            [id] => 2
                            [parent] => 1
                            [text] => Parent2
                            [children] => Array
                                (
                                    [3] => Array
                                        (
                                            [id] => 3
                                            [parent] => 2
                                            [text] => Sub1
                                            [children] => Array
                                                (
                                                )
                                        )
                                )
                        )
                )
        )
)