一、两种实现php无限极分类

设置原始数据

public function index()
    {
        $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($this->getTree1($items));
        print_r($this->getTree1($items));
    }

1. 使用php递归实现php无限极分类

通过foreach循环实现无限极分类这种方式比较好理解

public function getTree1($items,$pid=0)
    {
        $array = [];
        foreach ($items as $key => $item) {
            if( $item['pid'] == $pid )
            {
                $array[$key] = $val;
                $array[$key]['son'] = $this->getTree1( $items, $item['pid']);
            }
        }
        return $array;
    }

2.通过引用实现php无限极分类

/**
     * 递归加引用实现无限极分类
     * @param $items
     * @return array
     */
    public function getTree2($items)
    {
        $array = [];
        foreach ($items as $item)
        {
            if(isset($items[$item['pid']]))
            {
                $items[$item['pid']]['son'][] = &$items[$item['id']];
            }else {
                $array[] = &$items[$item['id']];
            }
        }
        return $array;
    }