# 简单吧简单吧，用动态变量不停的改变进行遍历
menu = {
"北京":{
"朝阳":{
"国贸":{
"CICC":{},
"HP":{},
"CCTV":{},
},
"望京":{
"陌陌":{},
"奔驰":{},
":{},
},
"三里屯":{
"优衣库":{},
"apple":{},
}
},
"昌平":{
"沙河":{
"老男孩":{},
"阿泰包子":{},
},
"天通苑":{
"链家":{},
"我爱我家":{},
},
"回龙观":{},
},
"海淀":{
"五道口":{
"谷歌":{},
"网易":{},
"Sohu":{},
"Sogo":{},
"快手":{},
},
"中关村":{
"youku":{},
"Iqiyi":{},
"汽车之家":{},
"新东方":{},
"腾讯":{},
},
},
},
"上海":{
"浦东":{
"陆家嘴":{
"CICC":{},
"高盛":{},
"摩根":{},
},
"外滩":{},
},
"闵行":{},
"静安":{},
"":{},
},
"山东":{
"济南":{},
"德州":{
"乐陵":{
"顶乌镇":{},
"城区":{},
},
"平原":{},
},
"青岛":{},
},
}
current_layer = menu #实现动态循环的初始变量
# parent_layer = menu
parent_layers = [] #保存父籍，最后一个元素永远都是父亲籍
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) #在进下一层之前把当前层进行尾部追加，即下一层的父亲籍
current_layer = current_layer[choice] #将要被遍历的字典范围根据用户输入进行缩减范围
elif choice == "b":
if parent_layers:
current_layer = parent_layers.pop()#进行最后一个的弹出并赋值返回父亲层
else:
print("无此项")