Python简单实现多级菜单

# -*- coding: utf-8 -*-
# @Time    : 2018-06-01 13:40
# @Author  : 超人
# @Email   : [e-mail]
# @File    : 简单实现多级菜单功能 (输入s返回首菜单,输入b返回上一菜单,输入o终止程序)
# @Software: PyCharm

current_layer = menu#字典,多级菜单
parent_layers=[]
while True:
    for key in current_layer:
        print(key)
    choice = input('>>>>>>>>>>>').strip()
    if len(choice) == 0: continue
    if choice in current_layer:
        # print(choice)
        parent_layers.append(current_layer)
        current_layer = current_layer[choice]
    elif choice == "b":
        if not len(parent_layers)==0:
            current_layer = parent_layers.pop()
        else:
            current_layer=menu
    elif choice =="s":
        current_layer = menu
    elif choice == "o":
        break
    else:
        print('没有此选项,重新输入'.center(50,"-"))