Getting the exception value in Python


Question

If I have that code:

try:
    some_method()
except Exception, e:

How can I get this Exception value (string representation I mean)?

1
209
7/3/2019 9:18:22 AM

Accepted Answer

use str

try:
    some_method()
except Exception as e:
    s = str(e)

Also, most exception classes will have an args attribute. Often, args[0] will be an error message.

It should be noted that just using str will return an empty string if there's no error message whereas using repr as pyfunc recommends will at least display the class of the exception. My take is that if you're printing it out, it's for an end user that doesn't care what the class is and just wants an error message.

It really depends on the class of exception that you are dealing with and how it is instantiated. Did you have something in particular in mind?

284
11/29/2010 9:23:27 PM

Use repr() and The difference between using repr and str

Using repr:

>>> try:
...     print x
... except Exception, e:
...     print repr(e)
... 
NameError("name 'x' is not defined",)
>>> 

Using str:

>>> 
>>> try:
...     print x
... except Exception, e:
...     print str(e)
... 
name 'x' is not defined
>>> 
>>> 

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