字典三级菜单之逐级添加内容

db = {

}
v = input(">>>")
db[v] = {}
print(db)

db = {

}
while True:
    v = input(">>>")
    db[v] = {}
    print(db)

db = {
    "上海": {},
    "北京":{
        "昌平":{
            "沙河":{},
            "回龙观":{},
        },
        "朝阳":{},
        "海淀":{},
    }
}
path = []
while True:
    temp = db
    for item in path:
        temp = temp[item]
    print("当前可选的所有子节点：", list(temp.keys()))

    choice = input('1:添加节点；2：查看节点（b/q)；\n >>>')
    if choice == "1":
        name = input("请输入要添加的节点名称：")
        temp[name] = {}
    elif choice == "2":
        name = input("请输入要查看的节点名称：")
        path.append(name)
    elif choice.lower() == "b":
        if path:                 #if path == True:
            path.pop()
    elif choice.lower() == "q":
        print(temp)          #输出当前字典后再退出
        break
    else:
        print("输入错误，请重新输入！")