views:

62

answers:

2

Is there a way to get a "prettier" exception rather than one prefaced with __main__MyExceptionTitle?

Example:

>>> class BadThings(Exception):
...     def __init__(self, msg):
...         self.msg = msg
...         return
... 
>>> class BadThings(Exception):
...     def __init__(self, msg):
...         self.msg = msg
...         return
...     def __str__(self):
...         return self.msg
... 
>>> raise BadThings("This is really, really bad")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
__main__.BadThings: This is really, really bad

I would like it to just say:

BadThings: This is really, really bad

Just as if one types:

>>> raise Exception("This, too, is really, really bad")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
Exception: This, too, is really, really bad

I would like the __main__. gone!

Thanks, Narnie

A: 

If you handle the exception, you can format the message any way you like:

>>> try:
...     raise BadThings("This is really, really bad")
... except BadThings, e:
...     print e.msg
... 
This is really, really bad
Johnsyweb
Gotcha. Thank you!
narnie
@narnie: "Gotcha. Thank you!" is traditionally expressed on StackOverflow as a little green tick to the left of the most helpful answer.
Johnsyweb
+1  A: 

I am not sure why you want to remove __main__ because that is the module name and when your exception would be in a appropriately named module, it would look beautiful not ugly e.g. myexceptions.BadException

Alternatively you can catch exception and print as you wish.

But if you want the uncaught exceptions to be printed as per your wish, try to set sys.excepthook e.g.

class BadThings(Exception): pass 

import traceback
def myexcepthook(type, value, tb):
    l = ''.join(traceback.format_exception(type, value, tb))
    print l

import sys
sys.excepthook = myexcepthook

raise BadThings("bad bad")

Output:

Traceback (most recent call last):
  File "untitled-1.py", line 12, in <module>
    raise BadThings("bad bad")
BadThings: bad bad

So in sys.excepthook you can modify exception, format it etc

Anurag Uniyal
I was just thinking from an end-user standpoint. They might not understand __main__., but I didn't know that it would print the module name, that is better, but they wouldn't understand that either. I see what you mean about catching the exceptions. I like your solution final above as it teaches me more about what is going on "behind the scenes."
narnie
Good, so you can select the answer :)
Anurag Uniyal