Adding Data to an Exception in Python

Question

I'm trying to create an exception that contains the typical string and an additional piece of data:

class MyException(RuntimeError):
    def __init__(self,numb):
        self.numb = numb

try:
    raise MyException("My bad", 3)
except MyException as me:
    print(me)

When I run the above I get the obvious complaint that I've got only two arguments in __init__ but I passed three. I don't know how to get the typical string into my exception and add data.

Adam Hughes · Accepted Answer · 2019-01-10 18:24:37Z

8

You can pass the first arg (arg1) into the parent exception's constructor and then do what you want with the second argument.

class MyException(RuntimeError):
    def __init__(self, arg1, arg2):
        super().__init__(arg1)
        print("Second argument is " + arg2)

Note - if using Python 2, the call to super() is replaced by super(MyException, self)

edited Jan 10, 2019 at 18:24

answered Jan 10, 2019 at 18:22

Adam Hughes

16.5k14 gold badges100 silver badges140 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

chepner Over a year ago

He shows exactly what he wants to do with the second argument: save it for later use. (In the example, it would be available as me.numb.)

Ray Salemi · Accepted Answer · 2019-01-10 18:31:54Z

8

The updated code based on the answer above looks like this:

class MyException(RuntimeError):
    def __init__(self,message,numb):
        super().__init__(message)
        self.numb = numb

try:
    raise MyException("My bad", 3)
except MyException as me:
    print(me)
    print(me.numb)

It outputs

    My bad
    3

answered Jan 10, 2019 at 18:31

Ray Salemi

5,9835 gold badges38 silver badges73 bronze badges

2 Comments

Adam Hughes Over a year ago

You actually might put this under your original question below a separator like: --------- UPDATE --------- PS - glad it works, I didn't actually test it and figured it had a typo

Ray Salemi Over a year ago

@AdamHughes I wondered about that, but it seemed to me that it would confuse people to see an answer under the question. I imagined they would stop reading.

Collectives™ on Stack Overflow

Adding Data to an Exception in Python

2 Answers 2

1 Comment

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related