PHP unlimited classification tree data formatting code example detailed explanation

function genTree($items,$id='id',$pid='pid',$son = 'children'){

  $tree = array(); //格式化的树

  $tmpMap = array(); //临时扁平数据

  foreach ($items as $item) {

    $tmpMap[$item[$id]] = $item;

  }

  foreach ($items as $item) {

    if (isset($tmpMap[$item[$pid]])) {

      $tmpMap[$item[$pid]][$son][] = &$tmpMap[$item[$id]];

    } else {

      $tree[] = &$tmpMap[$item[$id]];

    }

  }

  unset($tmpMap);

  return $tree;

}

$items1 = array(

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

);

var_dump(genTree($items1));

/**

 * 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'),

);

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

          )

      )

  )

)*/