PHP 递归方法实现无限分类两种实例

tree.php

<?php
/**
 * @link http://ideone.com/gAsKlI
 */
$items = array(
    array('id' => 1, 'pid' => 0, 'name' => '一级11'),
    array('id' => 11, 'pid' => 0, 'name' => 'www.111cn.net 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' => 13, 'pid' => 12, 'name' => '三级31'),
    array('id' => 9, 'pid' => 1, 'name' => '二级25'),
);

function formatTree($array, $pid = 0)
{
    $arr = $tem = array();
    foreach ($array as $v) {
        if ($v['pid'] == $pid) {
            $tem = formatTree($array, $v['id']);
            //判断是否存在子数组
            $tem && $v['children'] = $tem;
            $arr[] = $v;
        }
    }
    return $arr;
}

echo "<pre>";
print_r(formatTree($items));

/**
Array
(
    [0] => Array
        (
            [id] => 1
            [pid] => 0
            [name] => 一级11
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [pid] => 1
                            [name] => 二级21
                        )

                    [1] => Array
                        (
                            [id] => 3
                            [pid] => 1
                            [name] => 二级23
                        )

                    [2] => Array
                        (
                            [id] => 9
                            [pid] => 1
                            [name] => 二级25
                        )

                )

        )

    [1] => Array
        (
            [id] => 11
            [pid] => 0
            [name] => www.111cn.net 一级12
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 10
                            [pid] => 11
                            [name] => 二级22
                        )

                    [1] => Array
                        (
                            [id] => 12
                            [pid] => 11
                            [name] => 二级24
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 13
                                            [pid] => 12
                                            [name] => 三级31
                                        )

                                )

                        )

                )

        )

)
*/

tree1.php

<?php
/**
 * 递归无限级分类【先序遍历算】，获取任意节点下所有子孩子
 * @link http://ideone.com/pN8FPt
 * @param array $arrCate 待排序的数组
 * @param int $parent_id 父级节点
 * @param int $level 层级数
 * @return array $arrTree 排序后的数组
 */
function getMenuTree($arrCat, $parent_id = 0, $level = 0)
{
    static  $arrTree = array(); //使用static代替global
    if( empty($arrCat)) return FALSE;
    $level++;
    foreach($arrCat as $key => $value)
    {
        if($value['parent_id' ] == $parent_id)
        {
            $value[ 'level'] = $level;
            $arrTree[] = $value;
            unset($arrCat[$key]); //注销当前节点数据，减少已无用的遍历
            getMenuTree($arrCat, $value[ 'id'], $level);
        }
    }
   
    return $arrTree;
}


/**
 * 测试数据
 */
$arrCate = array(  //待排序数组
  array( 'id'=>1, 'name' =>'顶级栏目一', 'parent_id'=>0),
  array( 'id'=>2, 'name' =>'顶级栏目二', 'parent_id'=>0),
  array( 'id'=>3, 'name' =>'栏目三', 'parent_id'=>1),
  array( 'id'=>4, 'name' =>'栏目四', 'parent_id'=>3),
  array( 'id'=>5, 'name' =>'栏目五', 'parent_id'=>4),
  array( 'id'=>6, 'name' =>'栏目六', 'parent_id'=>2),
  array( 'id'=>7, 'name' =>'栏目七', 'parent_id'=>6),
  array( 'id'=>8, 'name' =>'栏目八', 'parent_id'=>6),
  array( 'id'=>9, 'name' =>'栏目九', 'parent_id'=>7),
);

header('Content-type:text/html; charset=utf-8'); //设置utf-8编码
echo '<pre>';
print_r(getMenuTree($arrCate, 0, 0));
echo '</pre>';