三级菜单的三个版本

1.这是我们通过一般方式进行的，就是按照正常的思路来写的，一步一步走

#_author:sangshijia
#date:2016/8/24
menu_map={
    "河南":{
        "郑州":["新密","登封","中牟"],
        "洛阳":["汝阳","伊川","嵩县"],
        "南阳":["西峡","方城","内乡"],
    },
    "河北":{
        "保定":["顺平","曲阳","徐水"],
        "邢台":["临城","清河","新河"],
        "邯郸":["广平","鸡泽","肥乡"],
    },
    "安徽":{
        "合肥":["长丰","肥东","肥西"],
        "毫州":["蒙城","利辛","涡阳"],
        "滁州":["凤阳","来安","定远"],
    },

}
flag=True
while True:
    for key in menu_map:
        print(key)
    choice=input("1，请输入省份，b返回上一级目录，d删除省份>>>:").strip()
    if choice =="b":
        break
        print("返回上一级目录")
    if choice =="d":
        choice_del=input("请输入需要删除的省份：").strip()
        del menu_map[choice_del]
    elif choice in menu_map:
        while True:
            for key2 in menu_map[choice]:
                print(key2)
            choice2 = input("2，请输入市，b返回上一级目录，d删除市>>>:").strip()
            if choice2 =="b":
                break
                print("返回上一级目录")
            if choice2 =="d":
                choice_del = input("请输入需要删除的市：").strip()
                del menu_map[choice][choice_del]
            elif choice2 in menu_map[choice]:
                while True:
                    for key3 in menu_map[choice][choice2]:
                        print(key3)
                    choice3=input("3，请输入县，b返回上一级目录，d删除县>>>:").strip()
                    if choice3 =="b":
                        break
                        print("返回上一级目录")
                    if choice3 =="d":
                        choice_del = input("请输入需要删除的县：").strip()
                        del menu_map[choice][choice2][choice3]
                    elif choice3 in menu_map[choice][choice2]:
                        print("last level")
                    elif choice3 not in menu_map[choice][choice2]:
                        choice3 = input("请输入添加的县>>：").strip()
                        menu_map[choice][choice2][choice3]={}
            elif choice2 not in menu_map[choice]:
                choice2 = input("请输入添加的市>>：").strip()
                menu_map[choice][choice2] = {}
    elif choice not in menu_map:
        choice = input("请输入添加的省>>：").strip()
    menu_map[choice] = {}

2.这是简便后的，代码少了很多，就是把上一部分的一些重复代码 简化而成的

#_author:sangshijia
#date:2016/8/26
menu={
    "河南":{
        "郑州":["新密","登封","中牟"],
        "洛阳":["汝阳","伊川","嵩县"],
        "南阳":["西峡","方城","内乡"],
    },
    "河北":{
        "保定":["顺平","曲阳","徐水"],
        "邢台":["临城","清河","新河"],
        "邯郸":["广平","鸡泽","肥乡"],
    },
    "安徽":{
        "合肥":["长丰","肥东","肥西"],
        "毫州":["蒙城","利辛","涡阳"],
        "滁州":["凤阳","来安","定远"],
    },

}
import sys
current_layer=menu
parent_layers=[]
while True:
    for key in current_layer:
        print(key)
    choice=input(">>>:").strip()
    if len(choice)==0:continue
    if choice in current_layer:
        parent_layers.append(current_layer)
        current_layer=current_layer[choice]
    elif choice=="b":
        if parent_layers:
            current_layer=parent_layers.pop()
    else:
        print("无此项")

3.通过文件把menu_map中的内容存储到新建的一个文件aaa里面，这样就可以把menu_map这一段内容注释掉，通过调用新文件aaa来执行，同时呢，也熟悉了文件的一些操作

,同时也添加了增加和删除这2个功能，但是我只能用老方法来实现文件的加入，

#_author:sangshijia
#date:2016/8/24
#f=open('menu_map',encoding='utf8')
# menu_map={
#     "河南":{
#         "郑州":["新密","登封","中牟"],
#         "洛阳":["汝阳","伊川","嵩县"],
#         "南阳":["西峡","方城","内乡"],
#     },
#     "河北":{
#         "保定":["顺平","曲阳","徐水"],
#         "邢台":["临城","清河","新河"],
#         "邯郸":["广平","鸡泽","肥乡"],
#     },
#     "安徽":{
#         "合肥":["长丰","肥东","肥西"],
#         "毫州":["蒙城","利辛","涡阳"],
#         "滁州":["凤阳","来安","定远"],
#     },
#
# }
# new_menu=str(menu_map)
# f=open("aaa","w",encoding='utf8')
# f.write(new_menu)
# f.close()
f=open("aaa","r",encoding='utf8')
menu_map=f.read()
menu_map=eval(menu_map)
flag=True
while True:
    for key in menu_map:
        print(key)
    choice=input("1，请输入省份，b表示返回上一级目录，d表示删除省份>>>:").strip()
    if choice =="b":
        break
        print("返回上一级目录")
    if choice =="d":
        choice_del=input("请输入需要删除的省份：").strip()
        del menu_map[choice_del]
    elif choice in menu_map:
        while True:
            for key2 in menu_map[choice]:
                print(key2)
            choice2 = input("2，请输入市，b表示返回上一级目录，d表示删除市>>>:").strip()
            if choice2 =="b":
                break
                print("返回上一级目录")
            if choice2 =="d":
                choice_del = input("请输入需要删除的市：").strip()
                del menu_map[choice][choice_del]
            elif choice2 in menu_map[choice]:
                while True:
                    for key3 in menu_map[choice][choice2]:
                        print(key3)
                    choice3=input("3，请输入县，b表示返回上一级目录，d表示删除县>>>:").strip()
                    if choice3 =="b":
                        break
                        print("返回上一级目录")
                    if choice3 =="d":
                        choice_del = input("请输入需要删除的县：").strip()
                        del menu_map[choice][choice2][choice3]
                    elif choice3 in menu_map[choice][choice2]:
                        print("last level")
                    elif choice3 not in menu_map[choice][choice2]:
                        choice3 = input("请输入添加的县>>：").strip()
                        menu_map[choice][choice2][choice3]={}
            elif choice2 not in menu_map[choice]:
                choice2 = input("请输入添加的市>>：").strip()
                menu_map[choice][choice2] = {}
    elif choice not in menu_map:
        choice = input("请输入添加的省>>：").strip()
    menu_map[choice] = {}