PHP无限极分类巧用引用生成树

首先看代码实现

 

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function generateTree($items){     $tree = array();     foreach($items as $item){         if(isset($items[$item['pid']])){             $items[$item['pid']]['son'][] = &$items[$item['id']];         }else{             $tree[] = &$items[$item['id']];         }     }     return $tree; } $items = array(     1 => array('id' => 1, 'pid' => 0, 'name' => '安徽省'),     2 => array('id' => 2, 'pid' => 0, 'name' => '浙江省'),     3 => array('id' => 3, 'pid' => 1, 'name' => '合肥市'),     4 => array('id' => 4, 'pid' => 3, 'name' => '长丰县'),     5 => array('id' => 5, 'pid' => 1, 'name' => '安庆市'), ); print_r(generateTree($items));

输出结果

 

 

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Array (     [0] => Array         (             [id] => 1             [pid] => 0             [name] => 安徽省             [son] => Array                 (                     [0] => Array                         (                             [id] => 3                             [pid] => 1                             [name] => 昆明国防路医院                             [son] => Array                                 (                                     [0] => Array                                         (                                             [id] => 4                                             [pid] => 3                                             [name] => 长丰县                                         )                                    )                            )                        [1] => Array                         (                             [id] => 5                             [pid] => 1                             [name] => 安庆市                         )                    )            )        [1] => Array         (             [id] => 2             [pid] => 0             [name] => 浙江省         )   )

果然是厉害，代码简洁精炼，无需递归，执行速度快。这是我偶然在一个网站上看到的，觉得很实用就收藏下来，分享给大家。

 

------------------------------------ 下面方框里是上一个博主提出的问题，我没看懂什么意思 ，惭愧！-------------------------------------

上面生成树方法还可以精简到5行：

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function generateTree($items){     foreach($items as $item)         $items[$item['pid']]['son'][$item['id']] = &$items[$item['id']];     return isset($items[0]['son']) ? $items[0]['son'] : array(); }

上面这种无限极分类数据树形结构化的方法值得借鉴。但是我觉得这段代码实际用途并不明显啊，你想取出格式化的树形数据还是要递归啊：

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/**  * 如何取数据格式化的树形数据  */ $tree = generateTree($items); function getTreeData($tree){     foreach($tree as $t){         echo $t['name'].'<br>';         if(isset($t['son'])){             getTreeData($t['son']);         }     } } getTreeData($tree);

不明白为什么他还要递归取出，如果把generateTree()的返回值 输出为json给前端不好吗？