php无限分类方法讲解

大家知道php无限分类方法吗?在一些复杂的系统中，要求对信息栏目进行无限级的'分类，以增强系统的灵活性。那么PHP是如何实现无限级分类的呢?

　　一、递归方法

复制代码 代码如下:

$items = array(

array('id'=>1,'pid'=>0,'name'=>'一级11'),

array('id'=>2,'pid'=>0,'name'=>'一级12'),

array('id'=>3,'pid'=>1,'name'=>'二级21'),

array('id'=>4,'pid'=>3,'name'=>'三级31'),

array('id'=>5,'pid'=>1,'name'=>'二级22'),

array('id'=>6,'pid'=>3,'name'=>'三级32'),

array('id'=>7,'pid'=>6,'name'=>'四级41'),

);

$i = 0;

function formatTree($arr, $pid = 0){

$tree = array();

$temp = array();

global $i;

if($arr){

foreach($arr as $k=>$v){

if($v['pid'] == $pid){//

$temp = formatTree($arr, $v['id']);

$temp && $v['son'] = $temp;

$tree[] = $v;

}

}

}

return $tree;

}

print_r(formatTree($items));

　　二、非递归方法

复制代码 代码如下:

function genTree($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' => '一级11'),

2 => array('id' => 2, 'pid' => 1, 'name' => '二级21'),

3 => array('id' => 3, 'pid' => 1, 'name' => '二级23'),

4 => array('id' => 4, 'pid' => 9, 'name' => '三级31'),

5 => array('id' => 5, 'pid' => 4, 'name' => '四级43'),

6 => array('id' => 6, 'pid' => 9, 'name' => '三级32'),

7 => array('id' => 7, 'pid' => 4, 'name' => '四级41'),

8 => array('id' => 8, 'pid' => 4, 'name' => '四级42'),

9 => array('id' => 9, 'pid' => 1, 'name' => '二级25'),

10 => array('id' => 10, 'pid' => 11, 'name' => '二级22'),

11 => array('id' => 11, 'pid' => 0, 'name' => '一级12'),

12 => array('id' => 12, 'pid' => 11, 'name' => '二级24'),

13 => array('id' => 13, 'pid' => 4, 'name' => '四级44'),

14 => array('id' => 14, 'pid' => 1, 'name' => '二级26'),

15 => array('id' => 15, 'pid' => 8, 'name' => '五级51'),

16 => array('id' => 16, 'pid' => 8, 'name' => '五级52'),

17 => array('id' => 17, 'pid' => 8, 'name' => '五级53'),

18 => array('id' => 18, 'pid' => 16, 'name' => '六级64'),

);

print_r(genTree($items));