如何在不使用引用的情況下從平面數組生成樹狀數組

Question

我一直在將平面數組轉換爲多維樹狀。 I have already done it, but I used references, which creates another set of problems down the line，所以我需要做這個沒有參考。

輸入數組：

Array 
[ 
1 =>[ 
     'content_id' => 1, 
     'sort_order' => 1, 
     'level' => 1 
    ], 
2 =>[ 
     'content_id' => 7, 
     'sort_order' => 2, 
     'level' => 2 
    ], 
3 =>[ 
     'content_id' => 4, 
     'sort_order' => 3, 
     'level' => 2 
    ], 
4 =>[ 
     'content_id' => 2, 
     'sort_order' => 4, 
     'level' => 3 
    ], 
5 =>[ 
     'content_id' => 3, 
     'sort_order' => 5, 
     'level' => 1 
    ], 
6 =>[ 
     'content_id' => 6, 
     'sort_order' => 6, 
     'level' => 1 
    ], 
7 =>[ 
     'content_id' => 5, 
     'sort_order' => 7, 
     'level' => 2 
    ] 
] 

輸出數組：

1 => [ 
    'id' = 1, 
    'visited' = 0, 
    'children' => [ 
      2 => [ 
        'id' => 7, 
        'visited' => 0, 
        'children' => [] 
      ], 
      3 => [ 
        'id' => 4, 
        'visited' => 0, 
        'children' => [ 
          4 => [ 
           'id' = 2, 
           'visited' = 0, 
           'children' => [] 
          ] 
      ] 
], 
5 => [ 
    'id' => 3, 
    'visited' => 0, 
    'children' => [] 
], 
6 => [ 
    'id' => 6, 
    'visited' => 0, 
    'children' => [ 
      7 => [ 
        'id' => 5, 
        'visited' => 0, 
        'children => [] 
      ] 
] 
] 

任何想法如何解決這樣的問題，而不必直接母公司的關係設置？我可以使用遞歸，但引用是問題。

Answer 1

哦，這種問題的確令我感到癢。所以，這裏是我的解決方案：

<?php 

$origArray = array(
    array('content_id' => 1, 'sort_order' => 1, 'level' => 1), 
    array('content_id' => 7, 'sort_order' => 2, 'level' => 2), 
    array('content_id' => 4, 'sort_order' => 3, 'level' => 2), 
    array('content_id' => 2, 'sort_order' => 4, 'level' => 3), 
    array('content_id' => 3, 'sort_order' => 5, 'level' => 1), 
    array('content_id' => 6, 'sort_order' => 6, 'level' => 1), 
    array('content_id' => 5, 'sort_order' => 7, 'level' => 2), 
); 

function sortByOrder($a, $b) { 
    if ($a['sort_order'] == $b['sort_order']) { 
     return 0; 
    } 
    return ($a['sort_order'] < $b['sort_order']) ? -1 : 1; 
} 

function createHierarchicalArray($arr) { 
    $result = array(); 
    foreach ($arr as $el) { 
     $result = insertArrayElement($result, $el['content_id'], $el['level']); 
    } 
    return $result; 
} 

function insertArrayElement($array, $id, $level, $currentLevel = 1) { 
    if ($level > $currentLevel) { 
     $ids = array_keys($array); 
     $currentId = end($ids); 
     if (!isset($array[$currentId]['children'])) { 
      $array[$currentId]['children'] = array(); 
     } 
     $array[$currentId]['children'] = insertArrayElement($array[$currentId]['children'], $id, $level, $currentLevel + 1); 
    } else { 
     $array[$id] = array(); 
    } 

    return $array; 
} 

// Could do without this, if the array is already sorted. Otherwise it's a necessary step. 
uasort($origArray, 'sortByOrder'); 

$result = createHierarchicalArray($origArray); 

var_dump($result); 

編輯：更改了代碼以合併問題中的更改。