Python入门：用字典实现三级菜单

data={
    '北京':{
        "昌平":{
            "沙河":["Oldboy","test"],
            "天通苑":["Leveo","HP"],
            "立水桥":["baidu","链家"]
        },
        "朝阳":{},
        "东城区":{}
    },
    '河北':{
        "邯郸":{
            "大名":["110","120"],
            "成安":["一山","二山"]
        },
        "保定":{...},
        "石家庄":{}
    },
    '河南':{
        "郑州":{},
        "周口":{},
        "南乐":{}
    }
} #字典存菜单信息
exit_flag=False #退出标志
while not exit_flag:
    for i in data:
        print(i)
    choice=input("1请选择进入：")
    if choice in data:
        while not exit_flag:
            for i1 in data[choice]:
                print("\t",i1)
            choice2=input("2请选择进入：")
            if choice2 in data[choice]:
                while not exit_flag:
                    for i2 in data[choice][choice2]:
                        print("\t\t",i2)
                    choice3=input("3请选择进入：")
                    if choice3 in data[choice][choice2]:
                        for i3 in data[choice][choice2][choice3]:
                            print("\t\t\t",i3)
                        choice4=input("最后一层，按b返回")
                        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