php两种无限分类方法实例

一、递归方法

$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

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));