python实现三级菜单

题目要求:

    (1). 运行程序输出第一级菜单
    (2). 选择一级菜单某项,输出二级菜单,同理输出三级菜单
    (3). 让用户选择是否要退出
    (4). 有返回上一级菜单的功能

遇到的问题:

1、TypeError: list indices must be integers or slices, not str

每次选到三级的时候就会报错,如下图:

python实现三级菜单

解决方案:

修改字典如下:

data = {
    "北京": {
        "一号线": {"四惠":{}, "大望路":{}, "*":{}, "西单":{}},

        "二号线": {"北京站":{}, "朝阳门":{}, "东直门":{}, "西直门":{}},

        "三号线": {"国贸":{}, "三元桥":{}, "知春路":{}, "巴沟":{}}

    },
    "上海": {
        "四号线": {"徐家汇":{}, "人民广场":{}, "延长路":{}, "共康路":{}, "呼兰路":{}},

        "五号线": {"东昌路":{}, "静安寺":{}, "江苏路":{}, "虹桥火车站":{}},

        "六号线": {"宝山路":{}, "赤峰路":{}, "曹阳路":{}, "虹桥路":{}, "宜山路":{}}

    },
    "广州": {
        "七号线": {"东山口":{}, "农讲所":{}, "烈士陵园":{}, "公园前":{}, "体育西路":{}},

        "八号线": {"黄边":{}, "纪念堂":{}, "三元里":{}, "白云公园":{}},

        "九号线": {"沙河顶":{}, "北京路":{}, "一德路":{}, "文化公园":{}}

    },
    "深圳": {
        "一号线": {"高新园":{}, "桃园":{}, "白石洲":{}, "华侨城":{}},

        "四号线": {"白石龙":{}, "明乐":{}, "少年宫":{}, "红山":{}},

        "五号线": {"大学城":{}, "兴东":{}, "西里":{}, "深圳北站":{}}

    },
}

完整代码如下:

#Author:Kelly
#coding=utf-8

data = {
    "北京": {
        "一号线": {"四惠":{}, "大望路":{}, "*":{}, "西单":{}},

        "二号线": {"北京站":{}, "朝阳门":{}, "东直门":{}, "西直门":{}},

        "三号线": {"国贸":{}, "三元桥":{}, "知春路":{}, "巴沟":{}}

    },
    "上海": {
        "四号线": {"徐家汇":{}, "人民广场":{}, "延长路":{}, "共康路":{}, "呼兰路":{}},

        "五号线": {"东昌路":{}, "静安寺":{}, "江苏路":{}, "虹桥火车站":{}},

        "六号线": {"宝山路":{}, "赤峰路":{}, "曹阳路":{}, "虹桥路":{}, "宜山路":{}}

    },
    "广州": {
        "七号线": {"东山口":{}, "农讲所":{}, "烈士陵园":{}, "公园前":{}, "体育西路":{}},

        "八号线": {"黄边":{}, "纪念堂":{}, "三元里":{}, "白云公园":{}},

        "九号线": {"沙河顶":{}, "北京路":{}, "一德路":{}, "文化公园":{}}

    },
    "深圳": {
        "一号线": {"高新园":{}, "桃园":{}, "白石洲":{}, "华侨城":{}},

        "四号线": {"白石龙":{}, "明乐":{}, "少年宫":{}, "红山":{}},

        "五号线": {"大学城":{}, "兴东":{}, "西里":{}, "深圳北站":{}}

    },
}
exit_flag = False
while not exit_flag:
    for i in data:
        print(i)
    choice = input("选择进入1>>:")
    if choice in data:
        while not exit_flag:
            for i2 in data[choice]:
                print("\t",i2)
            choice2 = input("选择进入2>>:")
            if choice2 in data[choice]:
                while not exit_flag:
                    for i3 in data[choice][choice2]:
                        print("\t\t",i3)
                    choice3 = input("选择进入3>>:")
                    if choice3 in data[choice][choice2]:
                        for i4 in data[choice][choice2][choice3]:
                            print("\t\t",i4)
                        choice4 = input("最后一层,按b返回,按q退出>>:")
                        if choice4 == 'b':
                            pass
                        elif choice4 == 'q':
                            exit_flag = True
                    if choice3 == 'b':
                        break
                    elif choice3 == 'q':
                        exit_flag = True
            if choice2 == 'b':
                break
            elif choice2 == 'q':
                exit_flag = True