一:制作要求
1.三级菜单
2.可依次选择进入各子菜单
3.所需新知识点:字典,列表
*本文通过三种方法完成,第一种:只使用循环,第二种:使用列表,第三种:使用字典
二:FlowChart流程图
与上图对应,实现方式图解:
while用来判断输入的数据和允许输入数据中的哪一项匹配,if来进行判断是否退出本次循环,
三:具体实现代码:
1.没有使用列表字典
#三级菜单 输入都是用一个变量 0120使用字典,列表 #思路:while
#定义一级菜单
msg='''
请输入你要进行的操作前面的索引(1,2,3,b): 1.北京
2.上海
3.香港
b.退出
'''
#定义二级菜单
msg_1='''
1.朝阳区
2.西城区
3.海淀区
b.返回上一级
'''
msg_2_2='''
1.西城区_A
2.西城区_B
3.西城区_C
b.返回上一级
'''
#定义三级菜单
msg_2_1='''
1.朝阳区_A
2.朝阳区_B
3.朝阳区_C
b.返回上一级
'''
while True:
#输出一级菜单:
print(msg)
select_input=input("请输入你的选择:")
#选项一
while select_input== "":
print(msg_1)
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
print(msg_2_1)
select_input_2 = input("请输入你的选择:")
if select_input_2=="b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1== "b":
break
#选项二
while select_input == "":
print(msg_1)
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
print(msg_2_1)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1 == "b":
break
#选项三
while select_input == "":
print(msg_1)
select_input_1 = input("请输入你的选择:")
while select_input_1 == 1:
print(msg_2_1)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(msg_2_2)
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1 == "b":
break
#选项四
if select_input=="b":
break
print("本次使用结束!")
2.使用列表
# 三级菜单 输入都是用一个变量 0120使用字典,列表 # 思路:while
# 通过定义列表进行选项存储
list=["北京","上海","香港","退出"]
list_1=["朝阳区","西城区","海淀区","返回上一级"]
list_1_1=["朝阳区_A","朝阳区_B","朝阳区_C","返回上一级"]
list_1_2=["西城区_A","西城区_B","西城区_C","返回上一级"]
while True:
# 输出一级菜单:
for i in list:
print(" \n%s: %s"%(list.index(i)+1,i))
select_input = input("请输入你的选择:")
# 选项一
while select_input == "":
for i in list_1:
print(" \n%s: %s" % (list_1.index(i) + 1, i))
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
for i in list_1_1:
print(" \n%s: %s" % (list_1_1.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
if select_input_1 == "":
break
# 选项二
while select_input == "":
for i in list_1:
print(" \n%s: %s" % (list_1.index(i) + 1, i))
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
if select_input_1 == "":
break
# 选项三
while select_input == "":
for i in list_1:
print(" \n%s: %s" % (list_1.index(i) + 1, i))
select_input_1 = input("请输入你的选择:")
while select_input_1 == 1:
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
while select_input_1 == "":
for i in list_1_2:
print(" \n%s: %s" % (list_1_2.index(i) + 1, i))
select_input_2 = input("请输入你的选择:")
if select_input_2 == "":
break
if select_input_1 == "":
break
# 选项四
if select_input == "":
break
print("本次使用结束!")
使用列表运行效果和第一种方法类似,只不过把返回的值改成了4,
3.使用字典
# 三级菜单 输入都是用一个变量 0120使用字典,列表 # 思路:while
# 通过字典进行选项存储
dic={
"1.北京":{
"1.朝阳区":["朝阳区_A","朝阳区_B","朝阳区_C","返回上一级"],
"2.西城区":["西城区_A","西城区_B","西城区_C","返回上一级"],
"3.海淀区":[],
"4.返回上一级":[]
},
"2.上海":{},
"3.香港":{},
"b.退出":{}
} while True:
# 输出一级菜单:
print(dic.keys())
select_input = input("请输入你的选择:")
# 选项一
while select_input == "":
print(dic["1.北京"].keys())
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1 == "b":
break
# 选项二
while select_input == "":
print(dic["1.北京"].keys)
select_input_1 = input("请输入你的选择:")
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1 == "b":
break
# 选项三
while select_input == "":
print(dic["1.北京"].keys)
select_input_1 = input("请输入你的选择:")
while select_input_1 == 1:
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
while select_input_1 == "":
print(dic["1.北京"]["1.朝阳区"])
select_input_2 = input("请输入你的选择:")
if select_input_2 == "b":
break
if select_input_1 == "b":
break
# 选项四
if select_input == "b":
break
print("本次使用结束!")
四:运行效果截图(第一种方法):
五:注意事项
1.Python虽然简单,但是一定要熟练掌握格式,有的时候差一个空格都会出错而且还不容易排除错误.
2.关于语句:
select_input=b
while int(select_input)==1
运行报错:ValueError: invalid literal for int() with base 10: 'b',
语法错误
出错原因:Python3.0以后的版本不能进行字符串转换类型之后与数字之间的比较与判断
所以改成:select_input=="1"