Question

我一直在尝试让我的代码重复执行一个列表，如果该列表为空，则可以正常工作，但是如果输入大于4，则我仍在尝试使python死机

我试图为此找到解决方案，但无法弄清楚应该去哪里

#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]
#Ask them what they want and repeat if left blank
while True:
    ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-4): ")
    print("")
    try:
        ComputerChoice_int = int(ComputerChoice)
    except ValueError:
        print("You can not leave this blank '%s', try again" % (ComputerChoice,))
        print("")
    else:
        break

我希望它会重复出现，但它带有

Traceback (most recent call last):
  File "\\hnhs-fs01\StudentUsers$\17031\Documents\11 DTG\1.7\Assement\Assessment computer.py", line 69, in <module>
    Computer = ComputerList[ComputerChoice_int -1]
IndexError: list index out of range

Answer 1

出什么问题了？这段代码可以完美地工作。

#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200", "test (5)"]
#Ask them what they want and repeat if left blank
while True:
    print(ComputerList)
    ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-%s): " % len(ComputerList))
    try:
        ComputerChoice_int = int(ComputerChoice) - 1
        if not -1 < ComputerChoice_int < len(ComputerList):
            raise ValueError
        print("ok")
        break
    except ValueError:
        print("Something went bad :/\n")

Answer 2

您可以执行以下操作，使用int(input())使一切变得更好+除了错误以外，您无需做任何事情。

ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]

while True:
    ComputerChoice = int(input("What computer would you like to buy?(Use the number beside it 1-4): "))

    if ComputerChoice not in range(1,5):
        print("invalid input")
    else:
        print("You selected {}".format(ComputerList[ComputerChoice-1]))
        # Do whatever here

Answer 3

它崩溃是因为您没有子句来捕获大于4的输入。如果字段不可转换为整数，则只会引发错误。现在您可以对4 in进行硬编码，但是更可靠的方法是使用列表的长度。如果添加或删除计算机，这将使代码更易于更新。

在这里我会做什么：

ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]

max_integer = len(ComputerList)
status = False 
while status == False:
   try:
      Choice = int(input("enter your choice"))
      if 0 < Choice <= max_integer:
         status = True
   except ValueError:
      print('input is invalid')
      pass

这可以缩短，但是我把它画了一点，以便您了解发生了什么事情

Answer 4

发生的事情是，您仅捕获ValueError（如字符串或空值）。数字4不是错误，因为4是整数。如果要使用ValueError和IndexError处理，则需要这样做：

#Create a list for when they select the computer they want
ComputerList = ["(1)Home Basic $900", "(2)Office $1200", "(3)Gamer $1500", "(4)Studio $2200"]
#Ask them what they want and repeat if left blank
while True:
    ComputerChoice = input("What computer would you like to buy?(Use the number beside it 1-4): ")
    print("")
    try:
        ComputerChoice_int = int(ComputerChoice)
        Computer = ComputerList[ComputerChoice_int -1]
    except Exception as e:
        if e.__class__.__name__ == "ValueError":
            print("You can not leave this blank '%s', try again" % (ComputerChoice,))
            print("")
        elif e.__class__.__name__ == "IndexError":
            print("You can not input numbers bigger than {}, try again".format(len(ComputerList)))
            print("")
    else:
        break

如何为输入重复输入

4 个答案: