用户定义和内置异常中的参数

Question

以下代码在执行时不会导致打印参数（即：不允许除以零）。它只提供来自-零除错误。那么，当内置错误消息可用时，用户定义的参数有什么用。

print "Enter the dividend"
dividend=input()
print "Enter the divisor"
divisor=input()
try:
    result=dividend/divisor
except "ZeroDivisonError",argument:
    print "Divide by Zero is not permitted n ",argument # Argument not getting printed
else:   
    print "Result=%f" %(result)

Answer 1

使你的异常通用工作：

dividend=int(input("Enter the dividend: "))
divisor=int(input("Enter the divisor: "))
try:
    result=dividend/divisor
except Exception,argument:
    print "Divide by Zero is not permitted n ",str(argument) # Argument not getting printed
else:   
    print "Result=%f" %(result)

如果要定义自己的异常，请按以下方式操作：

# Define a class inherit from an exception type
class CustomError(Exception):
    def __init__(self, arg):
        # Set some exception infomation
        self.msg = arg
try:
    # Raise an exception with argument
    raise CustomError('This is a CustomError')
except CustomError, arg:
    # Catch the custom exception
    print 'Error: ', arg.msg

你可以在这里找到这个模板：定义python异常的正确方法

Answer 2

"ZeroDivisonError"的拼写不正确，而且它不应该在"中。正确行：

    except ZeroDivisionError,argument:
    print "Divide by Zero is not permitted n ",argument