生成无限分类的结构

public function get_tree_1(array $list = array())
{
$root = array();
$node = array();

foreach ($list as $k => $v) {

list($id, $pid, $name, $path) = array_values($v);
$node[$id] = $v;

if(isset($node[$pid])) {
$node[$pid]['child'][$id] = &$node[$id];
}

if($pid == 0) {
$root[$id] = &$node[$id];
}

}

return $root;
}