php 递归树形结构

function tree($arr, $pid=0, $level=0){ ???static $tree = []; ???foreach($arr as $v){ ???????if($v[‘pid‘] == $pid){ ???????????$v[‘level‘] = $level; ???????????if($pid == 0){ ???????????????$v[‘name‘] = $v[‘name‘]; ???????????}else{ ???????????????$v[‘name‘] = str_repeat(‘　‘, $level).‘└─‘.$v[‘name‘]; ???????????} ???????????$tree[]=$v; ???????????tree($arr, $v[‘id‘], $level+1); ???????} ???} ???return $tree;}