1 $arr = array(
 2     0=>array(
 3         ‘cid‘=>1,
 4         ‘pid‘=>0,
 5         ‘name‘=>‘亚洲‘,
 6     ),
 7     1=>array(
 8         ‘cid‘=>2,
 9         ‘pid‘=>0,
10         ‘name‘=>‘北美洲‘,
11     ),
12     2=>array(
13         ‘cid‘=>3,
14         ‘pid‘=>1,
15         ‘name‘=>‘中国‘,
16     ),
17     3=>array(
18         ‘cid‘=>4,
19         ‘pid‘=>2,
20         ‘name‘=>‘美国‘,
21     ),
22     4=>array(
23         ‘cid‘=>5,
24         ‘pid‘=>3,
25         ‘name‘=>‘北京‘,
26     ),
27     5=>array(
28         ‘cid‘=>6,
29         ‘pid‘=>3,
30         ‘name‘=>‘河北‘,
31     ),
32     6=>array(
33         ‘cid‘=>7,
34         ‘pid‘=>5,
35         ‘name‘=>‘东城区‘,
36     ),
37     7=>array(
38         ‘cid‘=>8,
39         ‘pid‘=>5,
40         ‘name‘=>‘海淀区‘,
41     ),
42 );

 1 private function GetTree($arr,$pid,$step){
 2     global $tree;
 3     foreach($arr as $key=>$val) {
 4         if($val[‘pid‘] == $pid) {
 5             $flg = str_repeat(‘└―‘,$step);
 6             $val[‘name‘] = $flg.$val[‘name‘];
 7             $tree[] = $val;
 8             $this->GetTree($arr , $val[‘cid‘] ,$step+1);
 9         }
10     }
11     return $tree;
12 }

$newarr = $this->GetTree($arr, 0, 0);