无限极分类之查找子孙树

 1 <?php
 2
 3 header(‘content-type:text/html;charset=utf8‘);
 4 $area = array(
 5 array(‘id‘=>1,‘name‘=>‘安徽‘,‘parent‘=>0),
 6 array(‘id‘=>2,‘name‘=>‘海淀‘,‘parent‘=>7),
 7 array(‘id‘=>3,‘name‘=>‘濉溪县‘,‘parent‘=>5),
 8 array(‘id‘=>4,‘name‘=>‘昌平‘,‘parent‘=>7),
 9 array(‘id‘=>5,‘name‘=>‘淮北‘,‘parent‘=>1),
10 array(‘id‘=>6,‘name‘=>‘朝阳‘,‘parent‘=>7),
11 array(‘id‘=>7,‘name‘=>‘北京‘,‘parent‘=>0),
12 array(‘id‘=>8,‘name‘=>‘上地‘,‘parent‘=>2)
13 );
14
15
1
31
32 function subtree($arr,$id=0){
33      static $subs = array();  //静态属性只指向一个地址，不会每次引用都清空$subs;
34
35     foreach($arr as $v){
36         if($v[‘parent‘]  == $id){
37             $subs[] = $v;
38             subtree($arr,$v[‘id‘]);//
39         }
40     }
41     return $subs;
42 }
43 print_r(subtree($area,0));
44 ?>

static 总结

1:修饰类的属性和方法，静态属性，静态方法；

2：延迟绑定；static::method();

3:在函数中、方法中声明静态变量用