将一维数组转换为多维数组

Question

假设我有这个数组：

Array
(
  [0] => Array
  (
    [name] => ELECTRONICS
    [depth] => 0
  )
  [1] => Array
  (
    [name] => TELEVISIONS
    [depth] => 1
  )
  [2] => Array
  (
    [name] => TUBE
    [depth] => 2
  )
  [3] => Array
  (
    [name] => LCD
    [depth] => 2
  )
  [4] => Array
  (
    [name] => PLASMA
    [depth] => 2
  )
  [5] => Array
  (
    [name] => PORTABLE ELECTRONICS
    [depth] => 1
  )
)

我想把它转换成一个多维数组，这样深度比前一个元素高的直接元素就会进入到键为"children"的前一个数组中。像这样：

Array
(
  [0] => Array
  (
    [name] => ELECTRONICS
    [depth] => 0
    [children] => Array
    (
      [0] => Array
      (
        [name] => TELEVISIONS
        [depth] => 1
        [children] => Array
        (
          [0] => Array
          (
            [name] => TUBE
            [depth] => 2
          )
          [1] => Array
          (
            [name] => LCD
            [depth] => 2
          )
          [2] => Array
          (
            [name] => PLASMA
            [depth] => 2
          )
        )
      )
      [1] => Array
      (
        [name] => PORTABLE ELECTRONICS
        [depth] => 1
      )
    )
  )
)

非常感谢您的帮助。谢谢；）

Answer 1

这是我的破解方法…使用foreach循环和指针数组来跟踪一堆不同的父指针。

$multi_dimensional = array();
$last_depth = 0;
$parent = &$multi_dimensional;
$parents[$last_depth] = &$parent;

foreach ($start as $idx => $data) {
  // same/increasing depth
  if ($last_depth <= $data['depth']) {
    $parent['children'][] = $data;  
  } 
  // increasing depth
  if ($last_depth < $data['depth']) {
    $parents[$last_depth] = &$parent;
  }
  // decreasing depth
  if ($last_depth > $data['depth']) {
    $parent = &$parents[$data['depth']-1];
    $parent['children'][] = $data;  
  }
  // look ahead and prepare parent in increasing
  if (isset($start[$idx+1]) && $start[$idx+1]['depth'] > $data['depth']) {
    $last_insert_idx = count($parent['children'])-1;
    $parent = &$parent['children'][$last_insert_idx];
  }
  $last_depth = $data['depth'];
}
// initial values are in child "children" array
$result = $multi_dimensional['children'];

Answer 2

这是一个棘手的问题。我不确定这是否是实现这一目标的最佳方式，但它确实有效：

function flat_to_tree($array, $depth = 0)
{
  $out = array();
  $inCurrentDepth = true;
  foreach ($array as $key => $value) {
    if ($value['depth'] < $depth) {
      return $out;
    }
    if ($value['depth'] === $depth) {
      $inCurrentDepth = true;
      $out[] = $value;
    }
    if ($inCurrentDepth && $value['depth'] > $depth) {
      $inCurrentDepth = false;
      $out[$key - 1]['children'] = flat_to_tree(array_slice($array, $key), $value['depth']);
    }
  }
  return $out;
}

Answer 3

我为它的名称和递归性质道歉。此外，请注意，这个函数会"破坏"您的原始数组，所以如果您想保持，请使用克隆

function multiDimensionate(&$arr, $currentLevel = 0) {
  $root = array();
  foreach ($arr as &$elem){
    if ($elem["depth"] == $currentLevel) {
      $root[] = $elem;
      unset($elem);
    } else if ($elem["depth"] == $currentLevel + 1) {
      $root[count($root)-1]["children"] = multiDimensionate($arr,$elem["depth"]);      
    }
  }
  return $root;
}

编辑：正如coments中所指出的，以前的函数没有正常工作，这应该没问题，仍然有破坏原始数组的副作用。