<?php
/**
 * 取出多维数组的值，返回一维数组
 * @param $arr
 * @param array $res
 * @return array
 */
function arrayValues($arr, $res = []) {
    $values = array_values($arr);
    $arr = [];
    foreach ($values as &$item) {
        if (is_array($item)) {
            $arr = array_merge($item, $arr);
        } else {
            array_push($res, $item);
        }
    }
    if ($arr) {
        return arrayValues($arr, $res);
    } else {
        return array_values(array_unique($res));
    }
}

/**
 * 无限级结构
 * @param array $data 数组
 * @param string $primarykey 主键
 * @param string $parentkey 父级键
 * @param int $pid 父级id
 * @param int $f 级别
 * @return array
 */
function getCateList($list, $pid = 0, $primarykey = 'id', $parentkey = 'pid', $f = 0) {
    static $temp = [];
    foreach ($list as $val) {
        if ($val[$parentkey] == $pid) {
            $val['level'] = $f;
            $temp[] = $val;
            getCateList($list, $val[$primarykey], $primarykey, $parentkey, $f + 1);
        }
    }
    return $temp;
}

/**
 * 父子级树状结构
 * @param array $list
 * @param string $primary_key
 * @param string $parent_key
 * @return array|mixed
 */
function getTreeList($list, $primary_key = 'id', $parent_key = 'pid') {
    $temp = [];
    foreach ($list as $v) {
        $v['children'] = [];
        $temp[$v[$primary_key]] = $v;
    }
    foreach ($temp as $k => $v) {
        $temp[$v[$parent_key]]['children'][] = &$temp[$v[$primary_key]];
    }
    return isset($temp[0]['children']) ? $temp[0]['children'] : [];
}