day2-三级菜单---改良版

#!/usr/bin/env python

data = {
    ‘北京‘: {
        "昌平": {
            "望京1": {"奔驰", "默默"},
            "国贸2": ("cicc", "HP"),
        },
        "朝阳": {
            "望京1": {"奔驰", "默默"},
            "国贸1": ("cicc", "HP"),
        },
    },
    ‘山东‘: {
        "昌平": {
            "望京1": {"奔驰", "默默"},
            "国贸2": ("cicc", "HP"),
        },
        "朝阳": {
            "望京2": {"奔驰", "默默"},
            "国贸2": ("cicc", "HP"),
        },
    },
    ‘广东‘: {
        "昌平": {
            "望京1": {"奔驰", "默默"},
            "国贸2": ("cicc", "HP"),
        },
        "朝阳": {
            "望京3": {"奔驰", "默默"},
            "国贸4": ("cicc", "HP"),
        },
    },
}
current_layer = data
layerlist = list()
while True:
    for i in current_layer:
        print(i)
    choice = input("选择进入,按b返回,按q退出>>:")
    if choice in current_layer:
        try:
            layerlist.append(current_layer)
            current_layer = current_layer[choice]
        except TypeError:
            current_layer = current_layer
        continue
    elif choice.lower() == ‘b‘:
        try:
            current_layer = layerlist.pop()
        except IndexError:
            pass
        continue
    elif choice.lower() == ‘q‘:
        exit("bye~~")