Question

我找到了基于id＆lt; - ＆gt; parent创建JSON的示例PHP代码，它看起来像：

<?php

$rows = array(
array('id' => 1, 'parent' => 0, 'name' => 'John Doe'),
array('id' => 2, 'parent' => 1, 'name' => 'Sally Smith'),
array('id' => 3, 'parent' => 2, 'name' => 'Mike Jones'),
array('id' => 4, 'parent' => 3, 'name' => 'Jason Williams'),
array('id' => 5, 'parent' => 4, 'name' => 'Sara Johnson'),
array('id' => 6, 'parent' => 1, 'name' => 'Dave Wilson'),
array('id' => 7, 'parent' => 2, 'name' => 'Amy Martin'),
);
// create an index on id
$index = array();

foreach($rows as $row){
  $row['data'] = (object) [];
  $index[$row['id']] = $row;
}

// build the tree
foreach($index as $id => &$row){
  if ($id === 0) continue;
  $parent = $row['parent'];
  $index[$parent]['children'][] = &$row;
}
unset($row);

// obtain root node
$index = $index[0]['children'][0];

// output json
header('Content-Type: application/json');
echo json_encode($index, JSON_PRETTY_PRINT);

它工作正常，但如何显示特定ID的所有子记录？例如，我需要父2的所有成员，所以我尝试：

     $index = $index[2]['children'][0];

它只显示3条记录，它应显示4条记录（Amy Martin缺失）。谢谢。

Answer 1

这是因为您正在尝试获取0索引，因此仅显示第一层次结构。要访问所有子项，请从数据中删除[0]

应该是：

$index = $index[2]['children'];

Answer 2

你只得到3条记录，因为你的“孩子”嵌套在不同的级别上（第4级是在不同的级别上

Array
(
    [0] => Array
        (
            [id] => 3
            [parent] => 2
            [name] => Mike Jones
       ...
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 4
                            [parent] => 3
                            [name] => Jason Williams

                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 5
                                            [parent] => 4
                                            [name] => Sara Johnson
                                           ...

                                        )

                                )

                        )

                )

        )

    [1] => Array
        (
            [id] => 7
            [parent] => 2
            [name] => Amy Martin
            ...

        )

)

为了让所有的孩子都需要遍历并展平你的阵列。这可以使用interator完成。完整代码示例：

<?php

$rows = array(
array('id' => 1, 'parent' => 0, 'name' => 'John Doe'),
array('id' => 2, 'parent' => 1, 'name' => 'Sally Smith'),
array('id' => 3, 'parent' => 2, 'name' => 'Mike Jones'),
array('id' => 4, 'parent' => 3, 'name' => 'Jason Williams'),
array('id' => 5, 'parent' => 4, 'name' => 'Sara Johnson'),
array('id' => 6, 'parent' => 1, 'name' => 'Dave Wilson'),
array('id' => 7, 'parent' => 2, 'name' => 'Amy Martin'),
);
// create an index on id
$index = array();

foreach($rows as $row){
  $row['data'] = (object) [];
  $index[$row['id']] = $row;
}

// build the tree
foreach($index as $id => &$row){
  if ($id === 0) continue;
  $parent = $row['parent'];
  $index[$parent]['children'][] = &$row;
}
unset($row);

$array = $index[2]['children'];
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
$data = array();

foreach ($iterator as $leafValue) {
        if ( !$iterator -> hasChildren() ) {
                if ($iterator->key() == 'id') {
                        $data[$leafValue]['id'] = $leafValue;
                        $id = $leafValue;
                } else{
                        $data[$id][$iterator->key()] = $leafValue;
                }
        }
}


// output json
header('Content-Type: application/json');
echo json_encode($data, JSON_PRETTY_PRINT);

输出

{
    "3": {
        "id": 3,
        "parent": 2,
        "name": "Mike Jones"
    },
    "4": {
        "id": 4,
        "parent": 3,
        "name": "Jason Williams"
    },
    "5": {
        "id": 5,
        "parent": 4,
        "name": "Sara Johnson"
    },
    "7": {
        "id": 7,
        "parent": 2,
        "name": "Amy Martin"
    }
}

PHP id / parent，如何显示所有记录

2 个答案: