作业：
1、每周写一篇博客
2、编写登录接口
输入用户名密码
认证成功后显示欢迎信息
输错三次后锁定
3、多级菜单
三级菜单
可依次选择进入各子菜单
所需新知识点：列表、字典
data = {
"水果":{
"香蕉":{
"产地":["海南","马尔代夫"],
"价格":[9.9,29.9]
},
"苹果":{
"产地":["美国","山东"],
"价格":[1.2,5.5]
},
"荔枝":{
"产地":["台湾","云南","广西"],
"价格":[9,35,18]
},
},
"蔬菜":{
"菜花":{
"产地":["河北","河南"],
"价格":[25,13]
},
"西红柿":{
"产地":["怀柔","延庆"],
"价格":[0.5,1]
},
},
"调料":{
"酱油":{
"品牌":["海天","鲁花","李锦记"],
"价格":[25.5,35.5,15.5]
},
"食用盐":{
"品牌":["久大","白象"],
"价格":[5,9]
},
},
}
while True:
for i in data:
print(i)
choice = input("选择进入1>>:")
if choice in data:
while True:
for i2 in data[choice]:
print("\t",i2)
choice2 = input("输入b返回上一级菜单或选择进入2>>:")
if choice2 in data[choice]:
while True:
for i3 in data[choice][choice2]:
print("\t\t",i3)
choice3 = input("输入b返回上一级菜单或选择进入3>>:")
if choice3 in data[choice][choice2]:
for i4 in data[choice][choice2][choice3]:
print("\t\t",i4)
choice4 = input("输入b返回上一层，或输入q退出>>:")
if choice4 == "b":
pass
elif choice4 == "q":
exit()
if choice3 == "b":
break
elif choice3 == "q":
exit()
if choice2 == "b":
break
elif choice2 == "q":
exit()
else:
print("输入内容不存在。")
break 
