PHP无限极分类

<?php

$items = array(

    1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),

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

    3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),

    4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),

    5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'),

);

function generateTree($items){

    foreach($items as $item)

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

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

}

print_r(generateTree($items));