Question

所以我正在制作一个程序，需要几公里并将其转换为英里，然后反过来。当程序运行时，首先提示用户输入数字1或2以确定其千克到英里或千米到千克。如果用户输入除1或2以外的任何内容，我想编程显示“请输入值1或2”等，然后再次询问。有什么方法可以做到这一点？到目前为止，这是我的代码。

#Program that takes kilometers and converts it to miles VV
def main():
    choice = input("Kilometers to Miles/Miles to Kilometers? (1, 2): ")

    if choice == 1:
        kilo = float(input("How many kilometers will you be traveling?: "))
        convert = 0.62
        miles = kilo * convert
        print("You will be traveling about", miles, "miles!")
    else:

        milesTraveled = eval(input("How many miles will you be traveling?: "))
        convertTwo = milesTraveled // 0.62
        print("You will be traveling about", convertTwo, "kilometers!")
#end main
main()

Answer 1

最简单的方法是使用if语句。

user_input = input('Please enter either the value 1 or 2: ')
if(user_input == 1 or user_input == 2):
    # do stuff here (remove the pass and replace with code you want to execute)
    pass
else:
    user_input = input('Please enter either the value 1 or 2: ')

编辑，因为提供了代码

只需用以下内容替换你的else块：

elif(choice == 2):
    milesTraveled = eval(input("How many miles will you be traveling?: "))
    convertTwo = milesTraveled // 0.62
    print("You will be traveling about", convertTwo, "kilometers!")

然后添加：

else:
    choice = input('Please enter either the value 1 or 2: ')

Answer 2

你可以这样做;

try:
    choice = int(raw_input("Enter choice 1 or 2:"))
    if choice not in [1, 2]:
        raise ValueError()
except ValueError:
    print "Invalid Option, you needed to type a 1 or 2"
else:
    print "Your choice is", choice

Answer 3

您可以像这样使用if .. elif .. else .. construction：

#Program that takes kilometers and converts it to miles VV
def main():
    choice = input("Kilometers to Miles/Miles to Kilometers? (1, 2): ")

    if choice == 1:
        kilo = float(input("How many kilometers will you be traveling?: "))
        convert = 0.62
        miles = kilo * convert
        print("You will be traveling about", miles, "miles!")
    elif choice == 2:
        milesTraveled = eval(input("How many miles will you be traveling?: "))
        convertTwo = milesTraveled // 0.62
        print("You will be traveling about", convertTwo, "kilometers!")
    else:
        print("You have entered incorrect value! Please try again\n")
        main()
#end main
main()

Python编程：如果输入某个值，如何显示消息？

3 个答案: