Python第一周做业--三级菜单

循环用的多，之后再优化吧

三级菜单：

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. 菜单数据保存在文件中
4. 让用户选择是否要退出
5. 有返回上一级菜单的功能

data.txt 保存数据文件

{'河北':{ "石家庄":{"长安区":["oldboy","baidu","tencent"],"桥东区":["百事可乐","雪碧","芬达"]}, "邯郸":{ "丛台区":["新世纪","天鸿"]}},
    '北京':{"西城区":{"宣武门":["锦江之星","汉庭","如家"],"广安门":["希尔顿","速8","7天"]}}}

menu.py 运行文件

#!/use/bin/env python
# -*- coding:utf-8 -*-

f = open("data.txt","r",encoding="utf8")
f=f.read()
data=eval(f) # 把文本中内容转成字典

while True:
    for line in data:
        print(line)
    choice = input("选择进入1：")
    if choice in data:
        while True:
            for line2 in data[choice]:
                print("-->",line2)
            choice2 = input("选择进入2：")
            if choice2 in data[choice]:
                while True:
                    for line3 in data[choice][choice2]:
                        print("---->",line3)
                    choice3 = input("选择进入3：")
                    if choice3 in data[choice][choice2]:
                            for line4 in data[choice][choice2][choice3]:
                                print(line4)
                            choice4 = input("最后一层，返回请按b，退出请按q：")
                            if choice4 == "b":
                                pass
                            elif choice4 == "q":
                                exit()
                    elif choice3 == "b":
                        break
                    elif choice3 == "q":
                        exit()
            elif choice2 == "b":
                break
            elif choice2 == "q":
                exit()