<?php

/**

 * 树形数组

*/

//方法一

function genTree5($items) {

    foreach ($items as $item)

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

    return isset($items[0]['son']) ? $items[0]['son'] : array();

}

//方法二

function genTree9($items) {

$tree = array(); //格式化好的树

foreach ($items as $item)

if (isset($items[$item['pid']]))

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

else

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

return $tree;

}

$items = array(

    1 => array('id' => 1, 'pid' => 0, 'name' => '江西省'),

    2 => array('id' => 2, 'pid' => 0, 'name' => '黑龙江省'),

    3 => array('id' => 3, 'pid' => 1, 'name' => '南昌市'),

    4 => array('id' => 4, 'pid' => 2, 'name' => '哈尔滨市'),

    5 => array('id' => 5, 'pid' => 2, 'name' => '鸡西市'),

    6 => array('id' => 6, 'pid' => 4, 'name' => '香坊区'),

    7 => array('id' => 7, 'pid' => 4, 'name' => '南岗区'),

    8 => array('id' => 8, 'pid' => 6, 'name' => '和兴路'),

    9 => array('id' => 9, 'pid' => 7, 'name' => '西大直街'),

    10 => array('id' => 10, 'pid' => 8, 'name' => '东北林业大学'),

    11 => array('id' => 11, 'pid' => 9, 'name' => '哈尔滨工业大学'),

    12 => array('id' => 12, 'pid' => 8, 'name' => '哈尔滨师范大学'),

    13 => array('id' => 13, 'pid' => 1, 'name' => '赣州市'),

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

    15 => array('id' => 15, 'pid' => 13, 'name' => '于都县'),

    16 => array('id' => 16, 'pid' => 14, 'name' => '茅店镇'),

    17 => array('id' => 17, 'pid' => 14, 'name' => '大田乡'),

    18 => array('id' => 18, 'pid' => 16, 'name' => '义源村'),

    19 => array('id' => 19, 'pid' => 16, 'name' => '上坝村'),

);

echo '<pre>';

var_dump(genTree5($items)); 

var_dump(genTree9($items)); 

?>