无限极分类

数据库设计，与数据填入：

打印原始数据：

所有数据
Array
(
    [0] => Array
        (
            [id] => 5
            [name] => PHP
            [pid] => 0
            [sort] => 1
        )

    [1] => Array
        (
            [id] => 9
            [name] => Ajax
            [pid] => 3
            [sort] => 1
        )

    [2] => Array
        (
            [id] => 11
            [name] => 字符串
            [pid] => 5
            [sort] => 1
        )

    [3] => Array
        (
            [id] => 2
            [name] => DIV+CSS
            [pid] => 0
            [sort] => 2
        )

    [4] => Array
        (
            [id] => 8
            [name] => Jquery
            [pid] => 3
            [sort] => 2
        )

    [5] => Array
        (
            [id] => 10
            [name] => 函数
            [pid] => 5
            [sort] => 2
        )

    [6] => Array
        (
            [id] => 3
            [name] => JavaScript
            [pid] => 0
            [sort] => 3
        )

    [7] => Array
        (
            [id] => 4
            [name] => Apache
            [pid] => 0
            [sort] => 4
        )

    [8] => Array
        (
            [id] => 1
            [name] => HTML
            [pid] => 0
            [sort] => 5
        )

    [9] => Array
        (
            [id] => 6
            [name] => Linux
            [pid] => 0
            [sort] => 6
        )

    [10] => Array
        (
            [id] => 7
            [name] => 其他
            [pid] => 0
            [sort] => 7
        )

)

使用算法得到数据：

第一种最常用（常用于导航分类）：

第二种（常用于后台显示分类列表）：

/**
 * 数据融合函数，将其自己数据放置父级之后，组成一维数组    
 * @param  array   $cate 原始数据
 * @param  integer $pid  父级id
 * @param  string  $name 子级数组的键名
 * @return array   $arr  组合后数组
 */
static function mergeCateToTwoArray($cate, $pid = 0, $name = 'child') {
    $arr = array();

    foreach ( $cate as $v ) {
        if ( $v['pid'] == $pid ) {
            $v[$name] = self::mergeCateToTwoArray($cate, $v['id'], $name);
            $arr[] = $v;
        }
    }

    return $arr;
}

调用：
//将数据组合为多维数组
// $cate = Category::mergeCateToTwoArray($cate, 0, 'child');


结果：
Array
(
    [0] => Array
        (
            [id] => 5
            [name] => PHP
            [pid] => 0
            [sort] => 1
            [child] => Array
                (
                    [0] => Array
                        (
                            [id] => 11
                            [name] => 字符串
                            [pid] => 5
                            [sort] => 1
                            [child] => Array
                                (
                                )

                        )

                    [1] => Array
                        (
                            [id] => 10
                            [name] => 函数
                            [pid] => 5
                            [sort] => 2
                            [child] => Array
                                (
                                )

                        )

                )

        )

    [1] => Array
        (
            [id] => 2
            [name] => DIV+CSS
            [pid] => 0
            [sort] => 2
            [child] => Array
                (
                )

        )

    [2] => Array
        (
            [id] => 3
            [name] => JavaScript
            [pid] => 0
            [sort] => 3
            [child] => Array
                (
                    [0] => Array
                        (
                            [id] => 9
                            [name] => Ajax
                            [pid] => 3
                            [sort] => 1
                            [child] => Array
                                (
                                )

                        )

                    [1] => Array
                        (
                            [id] => 8
                            [name] => Jquery
                            [pid] => 3
                            [sort] => 2
                            [child] => Array
                                (
                                )

                        )

                )

        )

    [3] => Array
        (
            [id] => 4
            [name] => Apache
            [pid] => 0
            [sort] => 4
            [child] => Array
                (
                )

        )

    [4] => Array
        (
            [id] => 1
            [name] => HTML
            [pid] => 0
            [sort] => 5
            [child] => Array
                (
                )

        )

    [5] => Array
        (
            [id] => 6
            [name] => Linux
            [pid] => 0
            [sort] => 6
            [child] => Array
                (
                )

        )

    [6] => Array
        (
            [id] => 7
            [name] => 其他
            [pid] => 0
            [sort] => 7
            [child] => Array
                (
                )

        )

)


//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


/**
 * 数据融合函数，将其自己数据放置父级之后，组成一维数组    
 * @param  array   $cate  原始数据
 * @param  integer $pid   父级id
 * @param  integer $level 所属等级
 * @param  string  $html  分割符号
 * @return array   $arr   返回整理好的数据       
 */
static function mergeCateToOneArray($cate, $pid = 0, $level = 0, $html = '--') {
    $arr = array();

    foreach ( $cate as $v ) {
        if ( $v['pid'] == $pid ) {
            $v['level'] = $level + 1;
            $v['html']  = str_repeat($html, $level);
            $arr[] = $v;
            //将这一次递归，看成得到的一个数据
            $arr = array_merge($arr, self::mergeCateToOneArray($cate, $v['id'], $level+1, $html));
        }
    }

    return $arr;
}


调用：
//将数据组合为一维数组
// $cate = Category::mergeCateToOneArray($cate, 0, 0, '   --');


结果:
Array
(
    [0] => Array
        (
            [id] => 5
            [name] => PHP
            [pid] => 0
            [sort] => 1
            [level] => 1
            [html] => 
        )

    [1] => Array
        (
            [id] => 11
            [name] => 字符串
            [pid] => 5
            [sort] => 1
            [level] => 2
            [html] =>    --
        )

    [2] => Array
        (
            [id] => 10
            [name] => 函数
            [pid] => 5
            [sort] => 2
            [level] => 2
            [html] =>    --
        )

    [3] => Array
        (
            [id] => 2
            [name] => DIV+CSS
            [pid] => 0
            [sort] => 2
            [level] => 1
            [html] => 
        )

    [4] => Array
        (
            [id] => 3
            [name] => JavaScript
            [pid] => 0
            [sort] => 3
            [level] => 1
            [html] => 
        )

    [5] => Array
        (
            [id] => 9
            [name] => Ajax
            [pid] => 3
            [sort] => 1
            [level] => 2
            [html] =>    --
        )

    [6] => Array
        (
            [id] => 8
            [name] => Jquery
            [pid] => 3
            [sort] => 2
            [level] => 2
            [html] =>    --
        )

    [7] => Array
        (
            [id] => 4
            [name] => Apache
            [pid] => 0
            [sort] => 4
            [level] => 1
            [html] => 
        )

    [8] => Array
        (
            [id] => 1
            [name] => HTML
            [pid] => 0
            [sort] => 5
            [level] => 1
            [html] => 
        )

    [9] => Array
        (
            [id] => 6
            [name] => Linux
            [pid] => 0
            [sort] => 6
            [level] => 1
            [html] => 
        )

    [10] => Array
        (
            [id] => 7
            [name] => 其他
            [pid] => 0
            [sort] => 7
            [level] => 1
            [html] => 
        )

)



//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

/**
 * 根据子类id获取父类id
 * @param  [type] $cate [description]
 * @param  [type] $id   [description]
 * @return [type]       [description]
 */
static function getParents($cate, $id) {
    $arr = array();
    foreach ( $cate as $v ) {
        if ( $v['id'] == $id ) {
            $arr[] = $v;
            $arr = array_merge(self::getParents($cate, $v['pid']), $arr);
        }
    }
    return $arr;
}

调用：
$cate = Category::getParents($cate, 11);


结果:
Array
(
    [0] => Array
        (
            [id] => 5
            [name] => PHP
            [pid] => 0
            [sort] => 1
        )

    [1] => Array
        (
            [id] => 11
            [name] => 字符串
            [pid] => 5
            [sort] => 1
        )

)










//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


/**
 * 根据父类 ID 获取子级ID
 * @return [type] [description]
 */
static function getChildsId ($cate, $pid) {
    $arr = array();

    foreach ( $cate as $v ) {
        if ( $v['pid'] == $pid ) {
            $arr[] = $v['id'];
            $arr = array_merge($arr, self::getChildsId($cate, $v['id']));
        }
    }

    return $arr;
}

调用：
//根据父类id查找其下子级元素
$cate = Category::getChildsId($cate, 5);


结果：
Array
(
    [0] => 11
    [1] => 10
)