我们知道很多开源软件的无限分类都是采用递归的算法,但是我们知道递归即浪费时间,又浪费空间(内存),
上次我也分享了个我自己原创的无限分类生成树的方法,一热心php高手网友给我提出了宝贵的建议,我测试了一下,这段代码的时间非常之短,参考:
http://www.oschina.net/code/snippet_98719_11296,我再次整理了一下,发现数据库查询出数据之后,我们就已经定好了键值,因而实践中,我们一般会在model中查询出格式化成主键值对应数据的形式,因而我们可以直接用这样的数据,就少了一层循环。代码也非常简洁。
- /**
- * 此方法由@Tonton 提供
- * http://my.oschina.net/u/918697
- * @date 2012-12-12
- */
- function genTree5($items) {
- foreach ($items as $item)
- $items[$item['pid']]['son'][$item['id']] = &$items[$item['id']];
- return isset($items[0]['son']) ? $items[0]['son'] : array();
- }
-
- /**
- * 将数据格式化成树形结构
- * @author Xuefen.Tong
- * @param array $items
- * @return array
- */
- function genTree9($items) {
- $tree = array(); //格式化好的树
- foreach ($items as $item)
- if (isset($items[$item['pid']]))
- $items[$item['pid']]['son'][] = &$items[$item['id']];
- else
- $tree[] = &$items[$item['id']];
- return $tree;
- }
-
- $items = array(
- 1 => array('id' => 1, 'pid' => 0, 'name' => '江西省'),
- 2 => array('id' => 2, 'pid' => 0, 'name' => '黑龙江省'),
- 3 => array('id' => 3, 'pid' => 1, 'name' => '南昌市'),
- 4 => array('id' => 4, 'pid' => 2, 'name' => '哈尔滨市'),
- 5 => array('id' => 5, 'pid' => 2, 'name' => '鸡西市'),
- 6 => array('id' => 6, 'pid' => 4, 'name' => '香坊区'),
- 7 => array('id' => 7, 'pid' => 4, 'name' => '南岗区'),
- 8 => array('id' => 8, 'pid' => 6, 'name' => '和兴路'),
- 9 => array('id' => 9, 'pid' => 7, 'name' => '西大直街'),
- 10 => array('id' => 10, 'pid' => 8, 'name' => '东北林业大学'),
- 11 => array('id' => 11, 'pid' => 9, 'name' => '哈尔滨工业大学'),
- 12 => array('id' => 12, 'pid' => 8, 'name' => '哈尔滨师范大学'),
- 13 => array('id' => 13, 'pid' => 1, 'name' => '赣州市'),
- 14 => array('id' => 14, 'pid' => 13, 'name' => '赣县'),
- 15 => array('id' => 15, 'pid' => 13, 'name' => '于都县'),
- 16 => array('id' => 16, 'pid' => 14, 'name' => '茅店镇'),
- 17 => array('id' => 17, 'pid' => 14, 'name' => '大田乡'),
- 18 => array('id' => 18, 'pid' => 16, 'name' => '义源村'),
- 19 => array('id' => 19, 'pid' => 16, 'name' => '上坝村'),
- );
- echo "
"; Salin selepas log masuk
- print_r(genTree5($items));
- print_r(genTree9($items));
-
- //后者输出格式,前者类似,只是数组键值不一样,不过不影响数据结构
- /*
- Array
- (
- [0] => Array
- (
- [id] => 1
- [pid] => 0
- [name] => 江西省
- [son] => Array
- (
- [0] => Array
- (
- [id] => 3
- [pid] => 1
- [name] => 南昌市
- )
-
- [1] => Array
- (
- [id] => 13
- [pid] => 1
- [name] => 赣州市
- [son] => Array
- (
- [0] => Array
- (
- [id] => 14
- [pid] => 13
- [name] => 赣县
- [son] => Array
- (
- [0] => Array
- (
- [id] => 16
- [pid] => 14
- [name] => 茅店镇
- [son] => Array
- (
- [0] => Array
- (
- [id] => 18
- [pid] => 16
- [name] => 义源村
- )
-
- [1] => Array
- (
- [id] => 19
- [pid] => 16
- [name] => 上坝村
- )
-
- )
-
- )
-
- [1] => Array
- (
- [id] => 17
- [pid] => 14
- [name] => 大田乡
- )
-
- )
-
- )
-
- [1] => Array
- (
- [id] => 15
- [pid] => 13
- [name] => 于都县
- )
-
- )
-
- )
-
- )
-
- )
-
- [1] => Array
- (
- [id] => 2
- [pid] => 0
- [name] => 黑龙江省
- [son] => Array
- (
- [0] => Array
- (
- [id] => 4
- [pid] => 2
- [name] => 哈尔滨市
- [son] => Array
- (
- [0] => Array
- (
- [id] => 6
- [pid] => 4
- [name] => 香坊区
- [son] => Array
- (
- [0] => Array
- (
- [id] => 8
- [pid] => 6
- [name] => 和兴路
- [son] => Array
- (
- [0] => Array
- (
- [id] => 10
- [pid] => 8
- [name] =>
- 东北林业大学
- )
-
- [1] => Array
- (
- [id] => 12
- [pid] => 8
- [name] =>
- 哈尔滨师范大学
- )
-
- )
-
- )
-
- )
-
- )
-
- [1] => Array
- (
- [id] => 7
- [pid] => 4
- [name] => 南岗区
- [son] => Array
- (
- [0] => Array
- (
- [id] => 9
- [pid] => 7
- [name] => 西大直街
- [son] => Array
- (
- [0] => Array
- (
- [id] => 11
- [pid] => 9
- [name] =>
- 哈尔滨工业大学
- )
-
- )
-
- )
-
- )
-
- )
-
- )
-
- )
-
- [1] => Array
- (
- [id] => 5
- [pid] => 2
- [name] => 鸡西市
- )
-
- )
-
- )
- )*/
-
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