如何從 PHP 中的關聯數組構建多維數組樹？

Question

我試圖通過用它們各自的鍵“bandnumber”數組替換“s”和“d”鍵字符串值來從關聯數組構建多維數組樹，但似乎無法破解它。 我只能使它適用於陣列的第一個節點。

例如，我有以下數組：

$coiArray = array (
    array('bandnumber' => '02-BELG-2129929', 's'  =>'94-BELG-3237180', 'd' => '96-BELG-3156295' ),
    array('bandnumber' => '94-BELG-3237180', 's'  =>'88-BELG-3206112', 'd' => '88-BELG-3206173' ),
    array('bandnumber' => '88-BELG-3206112', 's'  =>'81-BELG-3238253', 'd' => '87-BELG-3008002' ),
    array('bandnumber' => '88-BELG-3206173', 's'  =>'', 'd' => '' ),
    array('bandnumber' => '96-BELG-3156295', 's'  =>'88-BELG-3206112', 'd' => '85-BELG-3049648' ),
    array('bandnumber' => '85-BELG-3049648', 's'  =>'', 'd' => '' ),
    array('bandnumber' => '81-BELG-3238253', 's'  =>'', 'd' => '' ),
    array('bandnumber' => '87-BELG-3008002', 's'  =>'', 'd' => '' ),
);

我正在嘗試以編程方式將上述數組轉換為以下多維數組樹：

$coiNestedArray = array('bandnumber' => '02-BELG-2129929',
               's' => array('bandnumber' => '94-BELG-3237180',
                     's' => array('bandnumber' => '88-BELG-3206112',
                           's' => array('bandnumber' => '81-BELG-3238253',
                                                 's' =>'',
                                                 'd' => ''
                           ),
                           'd' => array('bandnumber' => '87-BELG-3008002',
                                                 's' =>'',
                                                 'd' => ''
                           )
                     ),
                     'd' => array('bandnumber' => '88-BELG-3206173',
                           's' =>'',
                           'd' => ''
                     )
               ),
               'd' => array('bandnumber' => '96-BELG-3156295',
                     's' => array('bandnumber' => '88-BELG-3206112',
                           's' => array('bandnumber' => '81-BELG-3238253',
                                                 's' =>'',
                                                 'd' => ''
                           ),
                           'd' => array('bandnumber' => '87-BELG-3008002',
                                                 's' =>'',
                                                 'd' => ''
                           )
                     ),
                     'd' => array('bandnumber' => '85-BELG-3049648',
                           's' =>'',
                           'd' => ''
                     )
               )
        );

這是我迄今為止最接近的，但它只更新數組的第一個節點：

function findKey($coiarray, $bandnumber){
    $thisCol = array_column($coiarray, 'bandnumber');
    $found_key = array_search($bandnumber, $thisCol);
    return $found_key;
}


foreach ($coiArray as $key => $value) {

    $s = '';

    $found_key = findKey($coiArray,$coiArray[$key]['s']);
    if(isset($coiArray[$found_key])){
        $s = $coiArray[$found_key];
    }

    $d = '';

    $found_key = findKey($coiArray,$coiArray[$key]['d']);
    if(isset($coiArray[$found_key])) {
        $d = $coiArray[$found_key];
    }

    $coiArray[$key] = array('bandnumber' => $coiArray[$key]['bandnumber'], 's'  => $s, 'd' => $d );

}

我將在這里發布數組的整個轉儲重新構建，但這是$coiArray的第一個節點，來自var_dump($coiArray) ，您會注意到所有最內層嵌套的 ["s"] 和 [" d"] 鍵是字符串而不是它們各自的數組。

[0]=>
  array(3) {
    ["bandnumber"]=>
    string(15) "02-BELG-2129929"
    ["s"]=>
    array(3) {
      ["bandnumber"]=>
      string(15) "94-BELG-3237180"
      ["s"]=>
      string(15) "88-BELG-3206112"
      ["d"]=>
      string(15) "88-BELG-3206173"
    }
    ["d"]=>
    array(3) {
      ["bandnumber"]=>
      string(15) "96-BELG-3156295"
      ["s"]=>
      string(15) "88-BELG-3206112"
      ["d"]=>
      string(15) "85-BELG-3049648"
    }
  }

下面的示例是我手動創建的$coiNestedArray的第一個節點，以說明我要實現的目標。 請注意，每個 ["s"] 和 ["d"] 都是一個數組，派生自$coiArray 。

array(3) {
  ["bandnumber"]=>
  string(15) "02-BELG-2129929"
  ["s"]=>
  array(3) {
    ["bandnumber"]=>
    string(15) "94-BELG-3237180"
    ["s"]=>
    array(3) {
      ["bandnumber"]=>
      string(15) "88-BELG-3206112"
      ["s"]=>
      array(3) {
        ["bandnumber"]=>
        string(15) "81-BELG-3238253"
        ["s"]=>
        string(0) ""
        ["d"]=>
        string(0) ""
      }
      ["d"]=>
      array(3) {
        ["bandnumber"]=>
        string(15) "87-BELG-3008002"
        ["s"]=>
        string(0) ""
        ["d"]=>
        string(0) ""
      }
    }
    ["d"]=>
    array(3) {
      ["bandnumber"]=>
      string(15) "88-BELG-3206173"
      ["s"]=>
      string(0) ""
      ["d"]=>
      string(0) ""
    }
  }

我該如何解決這個問題？

Answer 1

您需要創建一個以bandnumbers 為鍵的關聯數組，以便您可以直接按bandnumbers 查找行。 然后訪問子項並通過引用將每個子項替換為該關聯數組中的相應值。

可選地檢測哪個bandnumber從未作為孩子被引用：它是根。 但是，如果您知道根頻帶編號，或者您知道它始終是第一個輸入行中的那個，那么您可以跳過最后一步。 最后提取該根的值（假設正好有一個）：

// Key the rows by their bandnumber:
foreach($coiArray as $row) {
    $hash[$row["bandnumber"]] = $row;
}
foreach($hash as &$row) {
    // Replace children with the corresponding row in the hash
    foreach(["s","d"] as $prop) {
        $child = $row[$prop];
        if (!isset($hash[$child])) continue;
        $row[$prop] =& $hash[$child];
        $children[] = $child; // Keep track of non-root bandnumbers
    }
}
// Only needed when you don't know which bandnumber is the root:
$root = current(array_diff(array_keys($hash), $children, ["s","d"]));

$result = $hash[$root];