如何从 PHP 中的关联数组构建多维数组树？

Question

我正在尝试通过将“s”和“d”键字符串值替换为它们各自的键“bandnumber”数组来从关联数组构建多维数组树，但似乎无法破解它。我只能使它适用于数组的第一个节点。

例如，我有以下数组：

$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' => '' ),
);

我正在尝试以编程方式将上述数组转换为以下多维数组树：

$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' => ''
                     )
               )
        );

这是迄今为止我最接近的，但它只更新数组的第一个节点：

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 );

}

我将在此处重新构建数组的整个转储，但这是$coiArray 的第一个节点，来自var_dump($coiArray)，您会注意到所有最内层嵌套的 ["s"] 和["d"] 键是字符串而不是它们各自的数组。

[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"
    }
  }

下面的示例是我手动创建的$coiNestedArray 中的第一个节点，以说明我想要实现的目标。请注意，每个 ["s"] 和 ["d"] 都是一个数组，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) ""
    }
  }

我该如何解决这个问题？

Answer 1

您需要创建一个以波段号为键的关联数组，以便您可以直接按波段号查找行。然后通过引用访问孩子并用该关联数组中的相应值替换每个孩子。

（可选）检测哪个频段号从未作为子项引用：它是根。但是，如果您知道根波段号，或者您知道它始终是第一个输入行中的那个，那么您可以跳过最后一步。最后提取该根的值（假设正好有一个）：

// 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];