如何以多个if语句结束程序，如果输入等于“quit”？

Question

我希望用户能够退出这个程序在任何时候输入“退出”。在

有没有一种方法可以用break语句的一个实例来实现这一点，还是需要在代码中的每个“if y==”语句中添加一个break？在

fruits = []
notfruits = []
print(fruits)
print(notfruits)

while len(fruits) < 3 or len(notfruits) < 3:   # replaced `and` with `or`
    print("Please enter fruits or notfruits:") #
    y = str(input(": "))                       # moved the input here
    if y == "fruits":
        while len(fruits) < 3:
            x = str(input(": "))
            x = x.strip()
            if x in notfruits:
                print(x + " is not a fruit!")
            elif x in fruits:
                print(x + " is already in the list!")
            else:
                fruits.append(x)
                print(fruits)
    elif y == "notfruits":
         while len(notfruits) < 3:
            x = str(input(": "))
            x = x.strip()
            if x in fruits:
                print(x + " is a fruit!")
            elif x in notfruits:
                print(x + " is already in the list!")
            else:
                notfruits.append(x)
                print(notfruits)
    elif y == "clearfruits":
        del fruits[:]
    elif y == "clearnotfruits":
        del notfruits[:]
    elif y == "quit":
        break
    else:
        print("Not a valid option!")

Answer 1

你可以使用

import sys
sys.exit(0)

立即停止执行进一步的程序语句，所以

^{pr2}$

应该行得通。在

文档：https://docs.python.org/3.5/library/sys.html#sys.exit