Python_简单三级菜单制作

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"