PHP无限极分类生成树方法，巧用引用
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;
}
$items = array(
1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),
2 => array('id' => 2, 'pid' => 0, 'name' => '浙江省'),
3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),
4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),
5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'),
);
print_r(generateTree($items));
Array
(
[0] => Array
(
[id] => 1
[pid] => 0
[name] => 安徽省
[son] => Array
(
[0] => Array
(
[id] => 3
[pid] => 1
[name] => 合肥市
[son] => Array
(
[0] => Array
(
[id] => 4
[pid] => 3
[name] => 长丰县
)
)
)
[1] => Array
(
[id] => 5
[pid] => 1
[name] => 安庆市
)
)
)
[1] => Array
(
[id] => 2
[pid] => 0
[name] => 浙江省
)
}
上面生成树方法还可以精简到5行：
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();
}
