用户定义并内置在例外中的参数

Question

下面的代码在执行时不会导致打印参数（即：不允许被零除）。它只会提供来自- ZeroDivisionError的内置错误消息。那么，当构建错误消息时，用户定义参数的用法是可用的。

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

“ZeroDivisonError”的拼写不正确，而且它不应该是我n“”。 正确的路线：

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

Answer 2

让你的异常通用的作品：

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) 

如果你想定义自己的例外，按照这种方式：

# 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：Proper way to define python exceptions