PHP无限分类生成树方法,引用,非递归

这个是核心方法

function generateTree($items){
    $tree = array();
    foreach($items as $item){
        if(isset($items[$item['pid']])){
            $items[$item['pid']]['son'][] =& $items[$item['id']];
        }else{
            $tree[] =& $items[$item['id']];
        }
	}
    return $tree;
}

### 这个是从发数据库中取出的数据
$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'),
);

print_r(generateTree($items));