多级菜单（增强版）

#__Author__ oliver
#__Date__ 2016/8/26


with open('省市县','r',encoding='utf-8') as f_read:
    data = f_read.readlines()   #将文件内容放入大列表
    # data = f_read.read()      #直接读出字符串
zone = eval(''.join(data))     #获取地区字典
current_layer = dict(zone)
parent_layer = []
while True:
    for key in current_layer:
        print(key)
    choice = input("Press <a> Add,press <m> Modify,press <d> Delete;press <b> back,press <q> Quit.
>>>:").strip()
    if len(choice) == 0:
        continue
    if choice in current_layer:
        parent_layer.append(current_layer)
        current_layer = current_layer[choice]
        if current_layer == {}:
            print("已到最后一级。")
    elif choice == 'b':
        if parent_layer:
            current_layer = parent_layer.pop()
    elif choice == 'q':
        while parent_layer != []:
            current_layer = parent_layer.pop()
        break
    elif choice == 'a': # add操作
        new_item = input("请输入新地区>>>").strip()
        if new_item in current_layer:
            print("地区%s已存在，请重新输入。
"%new_item)
        else:
            new_dic = {}
            current_layer.setdefault(new_item,new_dic) #增加菜单
    elif choice == 'd':
        del_item = input("请输入删除项>>>")
        if del_item in current_layer:
            del current_layer[del_item]              #删除菜单
        else:
            print("菜单中没有'%s'地区！
"%del_item)
    elif choice == 'm':
        modify_item = input("请输入修改项>>>").strip()
        save_value = current_layer[modify_item]    #保存用户输入的key对应的value
        modify_key = input("请输入新地区>>>").strip()
        del current_layer[modify_item]
        modify_dic = {modify_key : save_value}      #新键值对
        current_layer.update(modify_dic)            #将新的键值对添加到字典中
    else:
        print("无此项！
")
with open('省市县_new','w',encoding='utf-8') as f_write:
    f_write.write(str(current_layer))