onethink中 list_to_tree 函数 是如何返回数组的

Question

php

Answer 1

$a = array(
  array('id' => 1, 'pid' => 0, 'text' => 'a'),
  array('id' => 2, 'pid' => 1, 'text' => 'b'),
  array('id' => 3, 'pid' => 2, 'text' => 'c'),
  array('id' => 4, 'pid' => 3, 'text' => 'd'),
);
list_to_tree($a);function list_to_tree($list, $pk='id', $pid = 'pid', $child = '_child', $root = 0) {
  // 创建Tree
  $tree = array();
  if(is_array($list)) {
    // 创建基于主键的数组引用
    $refer = array();
    foreach ($list as $key => $data) {
      $refer[$data[$pk]] =& $list[$key];
    }
    foreach ($list as $key => $data) {
      // 判断是否存在parent
      $parentId = $data[$pid];
      if ($root == $parentId) {
        $tree[] =& $list[$key];
      }else{
        if (isset($refer[$parentId])) {
          $parent =& $refer[$parentId];
          $parent[$child][] =& $list[$key];
        }
      }
      echo "看看是怎么加进去的 $key\n";
      print_r($tree);
    }
  }
  return $tree;
}看看是怎么加进去的 0
Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [text] => a
        ))
看看是怎么加进去的 1
Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [text] => a
            [_child] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [pid] => 1
                            [text] => b
                        )                )        ))
看看是怎么加进去的 2
Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [text] => a
            [_child] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [pid] => 1
                            [text] => b
                            [_child] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 3
                                            [pid] => 2
                                            [text] => c
                                        )                                )                        )                )        ))
看看是怎么加进去的 3
Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [text] => a
            [_child] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [pid] => 1
                            [text] => b
                            [_child] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 3
                                            [pid] => 2
                                            [text] => c
                                            [_child] => Array
                                                (
                                                    [0] => Array
                                                        (
                                                            [id] => 4
                                                            [pid] => 3
                                                            [text] => d
                                                        )                                                )                                        )                                )                        )                )        ))