递归函数输出一个野生的多维数组，希望深入一层

Question

我正在尝试编写一个递归函数，以追溯到深度未知的嵌套的根类别。

[TABLE]

   cat_id | cat_name | cat_parent | cat_slug  
   //each category with a cat_parent of 0 is a root category

[/TABLE]

示例SQL结果：

Array
(
[0] => Array
    (
        [cat_id] => 17
        [cat_name] => another-test-category
        [cat_parent] => 16
        [cat_slug] => Another test category
    )

)

功能：

function breadcrumb($cat_id){

 $cat_nest =     
            SELECT *
            FROM table
            WHERE cat_id = '$cat_id' 
           //returns 1 row;

  $cat_array[$cat_id] = $cat_nest[0];  

   if($cat_nest[0]['cat_parent'] != 0){

   $cat_array[] = breadcrumb($cat_nest[0]['cat_parent']);
   } 

   return $cat_array;

 }

正在输出：

Array
(
[17] => Array
(
    [cat_id] => 17
    [cat_name] => test.example.1
    [cat_parent] => 16
    [cat_slug] => Test Example 1
)

[18] => Array
(
    [16] => Array
        (
            [cat_id] => 16
            [cat_name] => test.example.2
            [cat_parent] => 15
            [cat_slug] => Test Example 2
        )

    [17] => Array
        (
            [15] => Array
                (
                    [cat_id] => 15
                    [cat_name] => test.example.3
                    [cat_parent] => 6
                    [cat_slug] => Test Example 3
                )

            [16] => Array
                (
                    [6] => Array
                        (
                            [cat_id] => 6
                            [cat_name] => test.example.4
                            [cat_parent] => 2
                            [cat_slug] => Test Example 4
                        )

                    [7] => Array
                        (
                            [2] => Array
                                (
                                    [cat_id] => 2
                                    [cat_name] => test.example.5
                                    [cat_parent] => 0
                                    [cat_slug] => Test Example 5
                                )

                        )

                )

        )

)

)

所需的输出：

Array
(
[17] => Array
(
[cat_id] => 17
[cat_name] => test.example.1
[cat_parent] => 16
[cat_slug] => Test Example 1
)

[16] => Array
(
[cat_id] => 16
[cat_name] => test.example.2
[cat_parent] => 15
[cat_slug] => Test Example 2
)


[15] => Array
(
[cat_id] => 15
[cat_name] => test.example.3
[cat_parent] => 6
[cat_slug] => Test Example 3
)


[6] => Array
(
[cat_id] => 6
[cat_name] => test.example.4
[cat_parent] => 2
[cat_slug] => Test Example 4
)

[2] => Array
(
[cat_id] => 2
[cat_name] => test.example.5
[cat_parent] => 0
[cat_slug] => Test Example 5
)

)

Answer 1

我运行了一些测试，我认为该解决方案可以通过以下方式实现：

function breadcrumb($cat_id){

    $cat_nest =     
    SELECT *
    FROM table
    WHERE cat_id = '$cat_id' 
    //returns 1 row;

    $cat_array[$cat_id] = $cat_nest[0];  

    if($cat_nest[0]['cat_parent'] != 0){

        $cat_array = array_merge( $cat_array, breadcrumb($cat_nest[0]['cat_parent']) );
    } 

    return $cat_array;

}

这将完全按照您的需要维护ID，因为这只会合并数组，而不会使用$cat_array[]创建新索引>

Answer 2

考虑使用do-while循环：