Python 练习：三级菜单选择城市(二)

优化了上一个三级菜单选择城：http://www.cnblogs.com/klvchen/p/8646466.html

info = {
    'GuangDong':{
        'GuangZhou': ['TianHe', 'HaiZhu'],
        'MaoMing': ['MaoNan', 'DianBai']},
    'ShanDong': {
        'JiNan': ['ShiZhong', 'LiXia'],
        'QingDao': ['ShiNan', 'ShiBei']
    },
    'GuangXi': {
        'NanNin': ['WuNing', 'LongAn'],
        'GuiLing': ['YangSuo', 'QuanZhou']
    }
}
parent_list = []
current_layer = info
while True:
    for key in current_layer:
        print(key)
    choiced = input("Please select: [ b: back | q: exit]")
    if choiced in current_layer:
        parent_list.append(current_layer)
        try:
            current_layer = current_layer[choiced]
        except:
            print("This is last level")
            current_layer = parent_list.pop()
            continue
    elif choiced == "b":
        if parent_list:
            current_layer = parent_list.pop()
    elif choiced == "q":
        break
    else:
        print("Please input right optional.")
        continue

运行结果：