python中的列表数据结构的应用

如何解决python中的列表数据结构的应用

祝您生活愉快愉快。 我现在正在研究python中的高级数据结构，并且试图通过此练习来查找有关处理列表问题的答案。请帮我解决这个错误。以下是问题：

” 创建一个程序，使用户可以（1）将产品添加到列表中，（2）删除项目，并（3）打印列表并退出。

如果用户向列表中添加了一些内容，程序将询问“将添加什么？：”，并将其保存为列表中的最后一项。如果用户决定删除某项，则程序会通知用户列表中有多少项（列表中有[number]个项。“），并提示用户输入删除的项（”删除了哪个项？ ：“”。如果用户选择0，则第一个项目将被删除。当用户退出时，将为用户打印最终列表“以下项目保留在列表中：”，然后每行显示一个剩余项目。用户选择选项之外的任何内容（包括删除项目时），程序都会响应“选择不正确。”当程序正常工作时，它会打印出以下内容：

Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Apples
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Beer
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Carrots
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 2
There are 3 items in the list.
Which item is deleted?: 3
Incorrect selection.
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 2
There are 3 items in the list.
Which item is deleted?: 2
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 2
There are 2 items in the list.
Which item is deleted?: 0
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 4
Incorrect selection.
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 3
The following items remain in the list:
Beer

我的实现：

mylist=[]
while True:
    n=int(input("Would you like to\n(1)Add or\n(2)Remove items or\n(3)Quit?: "))
    if n==1:
        a=input("What will be added?: ") 
        mylist.append(a)
    if n==2:
        count=len(mylist)
        print("There are ",count," items in the list.")
        b=int(input("Which item is deleted?: "))
        for b in range(len(mylist)):
            mylist.pop(b)
        else:
            print("Incorrect selection.")
    if n==3:
        print("The following items remain in the list:\n",mylist)
        break

程序会打印出来，如下所示：

Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Apples
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Beer
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 1
What will be added?: Carrots
Would you like to
(1)Add or
(2)Remove items or
(3)Quit?: 2
There are  3  items in the list.
Which item is deleted?: 3
Traceback (most recent call last):
  File "ohjelma.py",line 12,in <module>
    mylist.pop(b)
IndexError: pop index out of range

我不知道我遇到了atm错误。请在这件事上给予我帮助！！！ 感谢您的时间和精力！

解决方法

列表中的索引从0开始。因此，在您的示例中，胡萝卜位于索引2。索引3不存在，因此无法从列表中弹出。 for循环似乎不起作用，您只需要检查输入是否小于列表的长度即可。您对n == 2的逻辑应该是这样的：

if n==2:
    count=len(mylist)
    print("There are ",count," items in the list.")
    b=int(input("Which item is deleted?: "))
    if b < count:
        mylist.pop(b)
    else:
        print("Incorrect selection.")