Simple code to implement infinite classification tree_PHP tutorial

[php]

$items = array(

1 => array('id' => 1, 'pid' => 0, 'name' => 'Jiangxi Province'),

2 => array('id' => 2, 'pid' => 0, 'name' => 'Heilongjiang Province'),

3 => array('id' => 3, 'pid' => 1, 'name' => 'Nanchang City'),

4 => array('id' => 4, 'pid' => 2, 'name' => 'Harbin City'),

5 => array('id' => 5, 'pid' => 2, 'name' => 'Jixi City'),

6 => array('id' => 6, 'pid' => 4, 'name' => 'Xiangfang District'),

7 => array('id' => 7, 'pid' => 4, 'name' => 'Nangang District'),

8 => array('id' => 8, 'pid' => 6, 'name' => 'Hexing Road'),

9 => array('id' => 9, 'pid' => 7, 'name' => 'Xidazhi Street'),

10 => array('id' => 10, 'pid' => 8, 'name' => 'Northeast Forestry University'),

11 => array('id' => 11, 'pid' => 9, 'name' => 'Harbin Institute of Technology'),

12 => array('id' => 12, 'pid' => 8, 'name' => 'Harbin Normal University'),

13 => array('id' => 13, 'pid' => 1, 'name' => 'Ganzhou City'),

14 => array('id' => 14, 'pid' => 13, 'name' => 'Gan County'),

15 => array('id' => 15, 'pid' => 13, 'name' => 'Yudu County'),

16 => array('id' => 16, 'pid' => 14, 'name' => 'Maodian Town'),

17 => array('id' => 17, 'pid' => 14, 'name' => 'Dataan Township'),

18 => array('id' => 18, 'pid' => 16, 'name' => 'Yiyuan Village'),

19 => array('id' => 19, 'pid' => 16, 'name' => 'Shangba Village'),

20 => array('id' => 20, 'pid' => 0, 'name' => 'Guangdong Province'),

21 => array('id' => 21, 'pid' => 20, 'name' => 'Guangzhou City'),

);

$t = array();

foreach ($items as $id => $item) {

if ($item['pid']) {

$items[$item['pid']][$item['id']] = &$items[$item['id']];

$t[] = $id;

}

}

foreach($t as $u) {

unset($items[$u]);

}

echo "

"; 

print_r($items);

http://www.bkjia.com/PHPjc/477827.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/477827.htmlTechArticle[php] $items = array( 1 = array(id = 1, pid = 0, name = Jiangxi Province ), 2 = array(id = 2, pid = 0, name = Heilongjiang Province), 3 = array(id = 3, pid = 1, name = Nanchang City), 4 = array(id = 4,...