递归php函数：发现错误的麻烦

Question

我在 laravel 中有一个家谱应用程序，我希望能够显示大纲视图（从很久以前的家庭开始，显示其孩子，显示那些孩子的家庭，那些家庭的孩子等）。

所以我做了这个递归 get_descendants 函数：

public static function get_descendants(Family $family, $results_array, $counter)
        {
            // start new round with a different temp array, to keep track
            $counter++;
            $this_array = "array_$counter";
            $$this_array = [];

            array_push ($$this_array, $family->caption);

            $kids = FamilyController::get_kids_of_family($family);

            // if family has no kids, return 0;
            if (!count($kids))
            {
                return 0;
            }

            else // add kids and check for their families
            {
                foreach ($kids as $kid) {
                    array_push ($$this_array, $kid->firstname);

                    // get families made by kid- for each one, call get_descendants
                    $families_made = FamilyController::get_families_person_made($kid);

                    foreach ($families_made as $new_family) {
                        array_push($$this_array, self::get_descendants($new_family, $$this_array, $counter));
                    }
                };

                // we've gone through the kids, add this round's array to the general results array
                array_push ($results_array, $$this_array);
            }
            return $results_array; 
        }

我已经通过打印语句确认循环是正确的，但是我保存结果的方式存在问题。我想要这样的东西，顶级家庭展示一次，孩子和他们的家庭嵌套：

array:1 [▼
  0 => array:4 [▼
    0 => "Padme & Anakin"
    1 => "Leia"
    2 => array:3 [▼
      0 => "Leia & Han"
      1 => "Kylo Ren"
    ]
    3 => "Luke"
  ]
]

但我得到了这个（中间有一个额外的重复）：

array:1 [▼
  0 => array:4 [▼
    0 => "Padme & Anakin"
    1 => "Leia"
    2 => array:3 [▼
      0 => "Padme & Anakin"
      1 => "Leia"
      2 => array:3 [▼
        0 => "Leia & Han"
        1 => "Kylo Ren"
      ]
    ]
    3 => "Luke"
  ]
]

谁能看出我的错误在哪里？

Answer 1

更新：事实证明，如果我摆脱最终的 results_array 并完全使用动态数组，它就可以工作，如下所示：

    public static function get_descendants(Family $family, $results_array, $counter)
    {
        // start new round with a different temp array, to keep track
        $counter++;
        $this_array = "array_$counter";
        $$this_array = [];

        array_push ($$this_array, $family->caption);

        $kids = FamilyController::get_kids_of_family($family);

        // if family has no kids, return 0;
        if (!count($kids))
        {
            return 0;
        }

        else // add kids and check for their families
        {
            foreach ($kids as $kid) {
                array_push ($$this_array, $kid->first);

                // get families made by kid- for each one, call get_descendants
                $families_made = FamilyController::get_families_person_made($kid);

                if (count($families_made))
                {
                    foreach ($families_made as $new_family) {

                        array_push($$this_array, self::get_descendants($new_family, $$this_array, $counter));
                    }
                }

            };

        }
        return $$this_array;
    }

Answer 2

使用动态数组看起来不必要的复杂，而且你不断填充相同的数组，所以这就是 Luke 出现在错误位置的原因。

更简洁的解决方案可能是非常具体地确定人们在数组中的位置，而不是使用动态数组名称。只是一个建议-

public static function getDescendants(Family $family)
{
    $family = [];
    $family['name'] = $family->caption;
    if ($kids = static::getKidsOfFamily($family)) {
        foreach ($kids as $kid) {
            $family['children'][] = $kid->firstname;
            $subfamilies = static::getFamiliesPersonMade($kid);
            foreach ($subfamilies as $subfamily) {
                $family['subfamilies'][] = static::getDescendants($subfamily);
            }
        };
    }

    return $family; 
}

会产生类似的东西

array [
    "name" => "Padme & Anakin"
    "children" => array [
        "Leia",
        "Luke"
    ],
    "subfamilies" => array [
        array [
            "name" => "Leia & Han"
            "children" => array [
                "Kylo Re"
            ]
        ]
    ]
]