【地区--三级菜单】_练习

#!/usr/bin/python
# -*- coding:utf-8 -*-
# Author:zhaosj
# 创建一个地区(area)字典
Area = {
    ‘北京‘:{
        ‘丰台区‘:{
            "右安门街道":[‘小明‘,‘小丽‘,‘小红‘],
            "太平桥街道":[‘小王‘,‘小号‘,‘小白‘],
            "西罗园街道":[‘小恒‘,‘小朱‘,‘小杨‘],
            "大红门街道":[‘小树‘,‘小青‘,‘小晴‘],
            "南苑街道":[‘小平‘,‘小童‘,‘小天‘]
        },
        ‘海淀区‘:{
            "羊坊店街道":[‘北京大学‘,"清华大学","北京师范大学"],
            "甘家口街道":[‘人民大学‘,"北京体育大学","北京邮电大学"],
            "八里庄街道":[‘鸟巢‘,"水立方","国家体育馆"],
            "紫竹院街道":[‘新东方‘,‘紫竹影院‘,‘金鼎大厦‘],
            "北下关街道":[‘北航‘,‘北理工‘,‘北工业‘]
        },
        ‘昌平区‘:{
            "城北街道":[‘‘], # 未完待完善
            "南口地区":[‘‘],
            "马池口地区":[‘‘],
            "沙河地区":[‘小汤山‘,‘老牛湾‘,‘史各庄‘],
            "城南街道":[‘‘]
        },
        ‘朝阳区‘:{
            "朝外街道":[‘‘],
            "劲松街道":[‘‘],
            "建外街道":[‘‘],
            "呼家楼街道":[‘‘],
            "八里庄街道":[‘‘]
        },
        ‘大兴区‘:{},
        ‘通州区‘:{},
        ‘东城区‘:{},
        ‘西城区‘:{}
    },
    ‘河北‘:{},
    ‘山东‘:{},
    ‘河南‘:{},
    ‘山西‘:{}
}
exit_entry = False   # 定义变量，变量值等于False(假)
while not exit_entry: # while 循环，当不等于exit_entry时
    for i in Area:
        print(i)
    choice = input("选择进入第一层>>>:")
    if choice in Area:
        while not exit_entry:
            for i2 in Area[choice]:
                print("\t",i2)
            choice2 = input("选择进入第二层>>>:")
            if choice2 in Area[choice]:
                while not exit_entry:
                    for i3 in Area[choice][choice2]:
                        print("\t\t",i3)
                    choice3 = input("选择进入第三层>>>:")
                    if choice3 in Area[choice][choice2]:
                        for i4 in Area[choice][choice2][choice3]: # 因为没有第4层，当输入这一层时，打印以上三层信息
                            print("\t\t",i4)
                        choice4 = input("已经是最后一层了，按b返回>>>:")
                        if choice4 == "b":
                            #break # 终止所有循环
                            pass # 占位符作用
                        elif choice4 == "q":
                            exit_entry = True
                    if choice3 == "b":
                        break
                    elif choice3 == "q":
                        exit_entry = True
            if choice2 == "b":
                break
            elif choice2 == "q":
                exit_entry = True