User Based Exception program not working

Question

This code does not work. Please tell what the error is....

class Error(Exception):
    def __init__(self,mssg):
        self.mssg = mssg

class InputError(Error):
    def __init__(self,val):
        super("Input Error")
        print val

Now I write in other part of my program

a = raw_input("Enter a number from 0-9: ")
if (ord(a)>47 and ord(a)<58):
    pass
else:
    raise InputError(a)

Now when I pass 'a' I get super expected a type but got a string I just want to pass that message to the base class and display it along with the wrong value.

What am I doing wrong here

score 1 · Accepted Answer · edited Dec 16 '10 at 14:57

1

The problem is that you're using super() incorrectly. The proper way is:

class InputError(Error):
    def __init__(self, val):
        super(InputError, self).__init__(val)
        print val

edited Dec 16 '10 at 14:57

Björn Pollex

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answered Dec 16 '10 at 14:55

brildum

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It seems tricker, but it follows with other Python idioms. Just as methods require you to explicitly pass `self` (which is the current instance), `super` requires you to explicitly pass in the current class. – brildum Dec 16 '10 at 16:05

score 0 · Answer 2 · answered Dec 16 '10 at 14:55

0

super() is used to access methods of a superclass that have been overridden in the subclass, not to instantiate the superclass with arguments.

What you appear to be trying to do is something like:

class InputError(Error):
    def __init__(self,val):
        super(InputError).__init__("Input Error")
        print val

although this isn't necessarily a good idea.

answered Dec 16 '10 at 14:55

Wooble

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Please tell how do you do it then.... lets say that there is a variable in base class and since it is common to all you want to just pass the value from the subclass what do you do?? – Dec 16 '10 at 14:57

score 0 · Answer 3 · answered Dec 16 '10 at 14:55

0

super is supposed to be called like this:

class InputError(Error):
    def __init__(self,val):
        super(InputError, self).__init__("Input Error")
        print val

answered Dec 16 '10 at 14:55

Abhinav Sarkar

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score 0 · Answer 4 · edited May 23 '17 at 12:26

0

super is a python builtin which takes the type of an object as its argument, not some (arbitrary) string, as you seem to have done. You probably mean

 super(InputError, self).__init__("Input Error")

[In Python 3.x, this can just be super().__init__("Input Error")]

Note that because of the name of your exception is already InputError, it's not clear what the string message adds to it...

See this question and the python docs.

edited May 23 '17 at 12:26

Community

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answered Dec 16 '10 at 14:56

Andrew Jaffe

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Yes It does .... Thanks a lot and I was referring to your saying that I am passing "Input Error" – Dec 16 '10 at 15:38

User Based Exception program not working

4 Answers4