Question

我正在尝试一个循环gooing，但后来我让用户输入5退出循环。我在python 3

def main():
    print("Welcome to the List Info Checker")
    printMenu()
    printValue = input("Please enter a number between 1 and 5(inclusive): ")
    while printValue != 5:
        if printValue == 1:
            print("1")
        elif printValue == 2:
           # allTheSame()
            print("2")
        elif printValue == 3:
           # allDifferent()
            print("3")
        elif printValue == 4:
           # sortThis()
            print("4")

main()

Answer 1

有两种方法可以打破while循环

让语句以某种方式发生变化，使其不再是True
使用break命令突破最低级别循环＆＃39;

因为只在循环之前询问用户输入，所以在循环开始后无法改变，导致无限循环。如果输入在循环内部，则可以通过用户输入5来打破它，因为每次循环重新启动时都会询问：

printValue = input("Please enter a number between 1 and 5(inclusive): ")

while printValue != 5:

    if printValue == 1:
        print("1")
    elif printValue == 2:
       # allTheSame()
        print("2")
    elif printValue == 3:
       # allDifferent()
        print("3")
    elif printValue == 4:
       # sortThis()
        print("4")

    printValue = input("Please enter a number between 1 and 5(inclusive): ")

Answer 2

您需要在循环中提示输入，否则它始终只是检查第一次输入的相同值。试试这个：

def main():
print("Welcome to the List Info Checker")
printMenu()
printValue = input("Please enter a number between 1 and 5(inclusive): ")
while printValue != 5:
    if printValue == 1:
        print("1")
    elif printValue == 2:
       # allTheSame()
        print("2")
    elif printValue == 3:
       # allDifferent()
        print("3")
    elif printValue == 4:
       # sortThis()
        print("4")
    printValue = input("Please enter a number between 1 and 5(inclusive): ")

main()

Answer 3

你可以使用“break”

print("Welcome to the List Info Checker")
printMenu()
while True:
    if printValue == 1:
        print("1")
    elif printValue == 2:
       # allTheSame()
        print("2")
    elif printValue == 3:
       # allDifferent()
        print("3")
    elif printValue == 4:
       # sortThis()
        print("4")
    elif printValue == 5:
        break

或最后两行

    else:
        break

如何让用户退出while循环

3 个答案: