Question

我的第二个问题：声明会抛出语法错误，不知道为什么？

这是用于检查sidewap数字的代码：

number1 = int(input("Enter a number between 0 and 9")) 
number2 = int(input("Enter a number between 0 and 9"))
number3 = int(input("Enter a number between 0 and 9"))


X = number1 + number2 + number3

while True:
        if X%3 !=0:
            print("Not a valid sideswap number")
            number1 = int(input("Enter a number between 0 and 9"))

            number2 = int(input("Enter a number between 0 and 9"))

            number3 = int(input("Enter a number between 0 and 9"))

        else:
            if number2 - number3 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

        else:           
            if number3 - number1 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

        else:
            if number1 - number2 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

Answer 1

而不是

else:
    if number2 - number3 == 1:

表达式是

elif number2 - number3 == 1:

查看documentation：

>>> if x < 0:
...     x = 0
...     print 'Negative changed to zero'
... elif x == 0:
...     print 'Zero'
... elif x == 1:
...     print 'Single'
... else:
...     print 'More'

Answer 2

python中没有像else if这样的东西。使用elif

例如：

else:           
    if number3 - number1 == 1:

将其更改为：

elif number3 - number1 == 1:

Answer 3

对于同一else，您不能有多个if。您要找的是elif:。示例 -

while True:
        if X%3 !=0:
            print("Not a valid sideswap number")
            number1 = int(input("Enter a number between 0 and 9"))

            number2 = int(input("Enter a number between 0 and 9"))

            number3 = int(input("Enter a number between 0 and 9"))

        elif number2 - number3 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

        elif number3 - number1 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

        elif number1 - number2 == 1:
                print("Not a valid sideswap number")
                number1 = int(input("Enter a number between 0 and 9"))

                number2 = int(input("Enter a number between 0 and 9"))

                number3 = int(input("Enter a number between 0 and 9"))

else：语句语法错误，简单的Python

3 个答案: