php 无限级分类查找父节点所有子节点【找出 某节点的子节点】

 

<?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
 * @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 $arrTree = []; //使用static代替global
    if (empty($arrCat)) return [];
    $level++;
    foreach ($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;
}

/**
 * 把db返回的二维数组集转换成Tree
 * @param $list
 * @param string $pk
 * @param string $pid
 * @param string $child
 * @param int $root
 * @return array
 */
function listToTree($list, $pk = 'id', $pid = 'pid', $child = '_child', $root = 0)
{
    $tree = [];
    if (is_array($list)) {
        // 创建基于主键的数组引用
        $refer = array();
        foreach ($list as $key => $data) {
            $refer[$data[$pk]] =& $list[$key];
        }
        foreach ($list as $key => $data) {
            // 判断是否存在parent
            $parentId = $data[$pid];
            if ($root == $parentId) {
                $tree[] =& $list[$key];
            } else {
                if (isset($refer[$parentId])) {
                    $parent =& $refer[$parentId];
                    $parent[$child][] =& $list[$key];
                }
            }
        }
    }
    return $tree;
}


/**
 * 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 '树状结构展示子类';
echo '<pre>';
print_r(listToTree($arrCate, $pk = 'id', $pid = 'parent_id', $child = 'children', $root = 0));
echo '</pre>';

echo '展示所有子类';
echo '<pre>';
print_r(getMenuTree($arrCate, 2, 0));
echo '</pre>';
?>

结果：

树状结构展示子类
Array
(
    [0] => Array
        (
            [id] => 1
            [name] => 顶级栏目一
            [parent_id] => 0
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 3
                            [name] => 栏目三
                            [parent_id] => 1
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 4
                                            [name] => 栏目四
                                            [parent_id] => 3
                                            [children] => Array
                                                (
                                                    [0] => Array
                                                        (
                                                            [id] => 5
                                                            [name] => 栏目五
                                                            [parent_id] => 4
                                                        )

                                                )

                                        )

                                )

                        )

                )

        )

    [1] => Array
        (
            [id] => 2
            [name] => 顶级栏目二
            [parent_id] => 0
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 6
                            [name] => 栏目六
                            [parent_id] => 2
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 7
                                            [name] => 栏目七
                                            [parent_id] => 6
                                            [children] => Array
                                                (
                                                    [0] => Array
                                                        (
                                                            [id] => 9
                                                            [name] => 栏目九
                                                            [parent_id] => 7
                                                        )

                                                )

                                        )

                                    [1] => Array
                                        (
                                            [id] => 8
                                            [name] => 栏目八
                                            [parent_id] => 6
                                        )

                                )

                        )

                )

        )

)
展示所有子类
Array
(
    [0] => Array
        (
            [id] => 6
            [name] => 栏目六
            [parent_id] => 2
            [level] => 1
        )

    [1] => Array
        (
            [id] => 7
            [name] => 栏目七
            [parent_id] => 6
            [level] => 2
        )

    [2] => Array
        (
            [id] => 9
            [name] => 栏目九
            [parent_id] => 7
            [level] => 3
        )

    [3] => Array
        (
            [id] => 8
            [name] => 栏目八
            [parent_id] => 6
            [level] => 2
        )

)