使用整数作为输入进行错误处理 [英] Error handling using integers as input

问题描述

我设置了这个程序，检查100中的标记进行测试。如果用户输入少于60，则应该说失败，如果超过59，则传递。

Ive set up this program that checks the mark out of 100 for a test. If the user inputs less than 60 it should say fail if more than 59, pass.

mark = int(input("Please enter the exam mark out of 100 "))
if mark < 60:
    print("\nFail")
elif mark < 101:
    print("\nPass")
else:
    print("\nThe mark is out of range")

如果用户没有输入整数，我如何让程序没有错误。

how do i get the program not to have errors if the user does not input the Integer.

请帮忙，有14岁儿童能理解的快速解决方案吗？

Please help, is there a quick solution that 14 year olds would understand?

推荐答案

将输入保存在变量中并转换为整数分开：

Save the input in a variable and convert to an integer separately:

import sys

i = input("Please enter the exam mark out of 100 ")
try:
    mark = int(i)
except ValueError:
    print('\nYou did not enter a valid integer')
    sys.exit(0)
if mark < 60:
    print("\nFail")
elif mark < 101:
    print("\nPass")
else:
    print("\nThe mark is out of range")

如果失败（即，您得到 ValueError ），则打印一条消息并退出。你可以解释（到14岁） int（）需要一个有效的整数作为输入，它会引发一个 ValueError 否则。这是有道理的，因为只有包含整数的字符串可以通过 int（）转换。

If it fails (i.e., you get a ValueError) then print a message and exit. You can explain (to a 14-year old) that int() needs a valid integer as input and it will raise a ValueError otherwise. That makes sense because only strings that contain an integer can be converted by int().

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