d_city = {

    "河南" : {"郑州" : ["二七区","中原区","回族管城区","惠济区","金水区","上街区"],

               "信阳" : ["浉河区","平桥区","羊山新区","南湾区","上天梯区","鸡公山区"]},

    "广东":{"广州":["越秀","海珠","荔湾","天河","白云","黄埔","南沙"],

                 "深圳":["罗湖区","龙岗区","福田区","南山区","盐田区","宝安区","大鹏新区"]}

d_city = {

    "河南" : {"郑州" : ["二七区","中原区","回族管城区","惠济区","金水区","上街区"],

               "信阳" : ["浉河区","平桥区","羊山新区","南湾区","上天梯区","鸡公山区"]},

    "广东":{"广州":["越秀","海珠","荔湾","天河","白云","黄埔","南沙"],

            "深圳":["罗湖区","龙岗区","福田区","南山区","盐田区","宝安区","大鹏新区"]}

}

while True:#保证 break 到这一级可以循环下去

    for index, key in enumerate(d_city.keys()):

        print(index, key)

        print('******************\n')

    value_f = input("请选择区域(退出请按q,返回请按b):").strip() #first 选择,选择第一个区域

    if value_f.isdigit():

        value_f = int(value_f)#保证输入为数字

        list_a = list(d_city.keys())[value_f]

        while True:#选择正确的区域编号后,进入下一级循环

            for index, key in enumerate(d_city[list_a]):#遍历序列中的元素以及它们的下标

                print(index, key)#显示遍历结果

            value_s = input("请选择地区(退出请按q,返回请按b):").strip()

            if value_s.isdigit():

                value_s = int(value_s)

                list_b = list(d_city[list_a].keys())[value_s]

                while True:

                    for index, key in enumerate(d_city[list_a][list_b]):

                        print(key)

                    value_d = input("退出请按q,返回请按b:").strip()

                    if value_d == 'q':

                        exit()

                    elif value_d == 'b':

                        break

                    else:print("请输入指定值")

            elif value_s == 'q':

                exit()

            elif value_s == 'b':

                break

    elif value_f == 'q':

            exit()

    elif value_f == 'b':

            break

#最后几行保证每一级都可以返回上一级,以及结束循环