如何修复"除了值错误"处的无效语法错误？

Question

我正在尝试编写一个简单的异常处理。然而，我似乎做错了什么。

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

这里有两个错误。首先，您需要括号来括起错误：

except (ValueError,IOError) as err:

其次，您需要一个try来配合except行：

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就不能使用except。