PHP实现无限级分类

function getTree($data)
{
    $items = [];
    foreach ($data as $v) {
        $items[$v['id']] = $v;
    }
    $tree = array();
    //格式化好的树
    foreach ($items as $item) {
        if (isset($items[$item['pid']])) {
            $items[$item['pid']]['son'][] = &$items[$item['id']];
        } else {
            $tree[] = &$items[$item['id']];
        }
        return $tree;
    }
}