如何修复“except ValueError”处的无效语法错误？

Question

我试图编写一个简单的异常处理。但我好像做错了什么。

def average():
    TOTAL_VALUE = 0
    FILE = open("Numbers.txt", 'r')

    for line in FILE:
        AMOUNT = float(line)
        TOTAL_VALUE += AMOUNT
        NUMBERS_AVERAGE = TOTAL_VALUE / AMOUNT
    print("the average of the numbers in 'Numbers.txt' is :",
        format(NUMBERS_AVERAGE, '.2f')) 

    FILE.close()

    except ValueError,IOError as err:
        print(err)

average()

> line 14
>         except ValueError as err:
>              ^
>     SyntaxError: invalid syntax

Answer 1

这里有两件事不对。首先，需要用括号将错误括起来：

except (ValueError,IOError) as err:

第二，您需要一个try来与该except行一起：

def average():
    try:
        TOTAL_VALUE = 0
        FILE = open("Numbers.txt", 'r')

        for line in FILE:
            AMOUNT = float(line)
            TOTAL_VALUE += AMOUNT
            NUMBERS_AVERAGE = TOTAL_VALUE / AMOUNT
        print("the average of the numbers in 'Numbers.txt' is :",
            format(NUMBERS_AVERAGE, '.2f')) 

        FILE.close()

    except (ValueError,IOError) as err:
        print(err)

没有try不能使用except。