用递归实现：menu = {'北京': {'海淀': {'五道口': {'soho': {},'网易': {},'google': {}},'中关村': {'爱奇艺': {},'汽车之家': {},'youku': {},},'上地': {'百度': {},},},'昌平': {'沙河': {'老男孩': {},'北航': {},},'天通苑': {},'回龙观': {},},'朝阳': {},'东城': {},},'上海': {'闵行': {"人民广场": {'炸鸡店': {}}},'闸北': {'火车战': {'携程': {}}},'浦东': {},},'山东': {},
}
def threeMenu(dic):while 1:for k in dic:print(k)key = input('输入城市(按b返回上一层,按q退出)：')if key == 'b' or key == 'q': return keyelif key in dic.keys() and dic[key]:ret = threeMenu(dic[key])if ret == 'q': return retelif (not dic.get(key)) or (not dic[key]):continue

用堆栈实现
menu = {'北京': {'海淀': {'五道口': {'soho': {},'网易': {},'google': {}},'中关村': {'爱奇艺': {},'汽车之家': {},'youku': {},},'上地': {'百度': {},},},'昌平': {'沙河': {'老男孩': {},'北航': {},},'天通苑': {},'回龙观': {},},'朝阳': {},'东城': {},},'上海': {'闵行': {"人民广场": {'炸鸡店': {}}},'闸北': {'火车战': {'携程': {}}},'浦东': {},},'山东': {},
}l = [menu]
while l:for k in l[-1]:print(k)key = input('输入城市(按b返回上一层,按q退出)：')if key in l[-1].keys() and l[-1][key]:l.append(l[-1][key])elif key == 'b':l.pop()elif key == 'q':breakelse:continue

#!/user/bin/env python
#-*-coding:utf-8 -*-
#Author: qinjiaxi
'''需求：
1.设计一个三级菜单
2.在任意时候可以返回上级菜单
3.在任何一级菜单里面可以随时退出程序思路：设计一个嵌套字典用于存储菜单内容--->利用嵌套循环打印每一级的内容--->然后判断输入条件根据输入条件选择是否退出和返回上级
'''
data = {"武汉":{"光谷":{"关山":['文华','华科','湖科']},"江夏":{"郊外":['湖经','楚天','纺大']}},"北京":{'朝阳':{'a':[1,2,3]}},"上海":{"市内":{'b':[2,3,4]}}
}
print(data)
exit_flag = False#设置一个退出标志
while not exit_flag:for i in data:print(i)#第一层choice = input('选择进入1>>>:')if choice in data:while not exit_flag:for i2 in data[choice]:print('\t', i2)#第二层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)#第三层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>>>:')if choice4 == 'b':passelif choice4 == 'q':exit_flag = Trueif choice3 == 'b':breakelif choice3 == 'q':exit_flag = Trueif choice2 == 'b':breakelif choice2 == 'q':exit_flag = Trueelif choice == 'q':exit_flag = True

# _author : Ahern Li
# @_date : 2017/9/12

menu = {'浙江省':{'杭州市':{'余杭区':{'中泰':{},'临平':{}},'西湖区':{'西湖':{},'留下':{}}},'温州市':{'苍南县':{'灵溪':{},'龙港':{}},'瑞安县':{'安阳':{},'锦湖':{}}}},'广东省':{'广州市':{'越秀区':{'人民路':{},'北京路':{}},'荔湾区':{'沙面':{},'龙津':{}}},'珠海市':{'香洲区':{'拱北':{},'吉大':{}},'金湾区':{'红旗镇':{},'平沙镇':{}}}}}# 返回标记
q_flag = True
# 退出标记
Q_flag = True
# 返回，退出标记出现False退出循环
while q_flag and Q_flag:# 遍历打印省份for i in menu:print(i)province = input('请输入要查找的省份(Q,退出):').strip()if province in menu:while q_flag and Q_flag:for i in menu[province]:print(i)city = input('请输入要查找的市(q,返回 或 Q,退出):').strip()if city in menu[province]:while q_flag and Q_flag:for i in menu[province][city]:print(i)county = input('请输入要查找的区或县(q,返回 或 Q,退出):').strip()if county in menu[province][city]:while q_flag and Q_flag:for i in menu[province][city][county]:print(i)# 提示最后一页，输入格式choice = input('最后一页! q,返回 或 Q,退出:').strip()if choice == 'q':# 配合 else: q_flag = True 退出该层循环，返回上层循环q_flag = Falseelif choice == 'Q':# 退出大循环Q_flag = Falseelse:# 提示输入不合法print('输入错误!')# 改回 q_flag 的值，实现只退出一层循环else:q_flag = Trueelif county == 'q':q_flag = Falseelif county == 'Q':Q_flag = Falseelse:print('输入错误!')else:q_flag = Trueelif city == 'q':q_flag = Falseelif city == 'Q':Q_flag = Falseelse:print('输入错误!')else:q_flag = Trueelif province == 'Q':Q_flag = Falseelse:print('输入错误!')

# _author : Ahern Li
# @_date : 2017/9/12

menu = {'浙江省':{'杭州市':{'余杭区':{'中泰':{},'临平':{}},'西湖区':{'西湖':{},'留下':{}}},'温州市':{'苍南县':{'灵溪':{},'龙港':{}},'瑞安县':{'安阳':{},'锦湖':{}}}},'广东省':{'广州市':{'越秀区':{'人民路':{},'北京路':{}},'荔湾区':{'沙面':{},'龙津':{}}},'珠海市':{'香洲区':{'拱北':{},'吉大':{}},'金湾区':{'红旗镇':{},'平沙镇':{}}}}}current_layer = menu  # 实现动态循环
parent_layer = []  # 保留所有父层，最后一个元素永远为父层while True:print() # 仅为了打印美观for i in current_layer:   # 遍历打印地址print(i)choice = input('请在下方输入查询地址\n>>>:').strip()if choice in current_layer:if current_layer[choice]:  # 判断是否为末层parent_layer.append(current_layer) # 进入子层前，添加当前层作为父层current_layer = current_layer[choice]  # 修改子层else:print('当前是最后一页')elif choice == '':continueelif choice == 'q':   # 返回上层if parent_layer:  # 判断 parent_layer 是否为空current_layer = parent_layer.pop() # 取出当前层父层# 退出循环elif choice == 'Q':breakelse:print('输入错误!')