What's the difference between "KeyError" and "KeyError as e"?

Question

When writing try/except statements, whether I use

except KeyError:

or

except KeyError as e:

I get the same result.

What is the difference between the two? Is KeyError as e just more specific/custom?

You get the actual exception object as the variable `e`. Apart from that, there is no difference. — Niklas R, Nov 19 '14 at 15:58
You can often avoid sounding stupid by [reading the docs](https://docs.python.org/2/tutorial/errors.html#handling-exceptions) and answering the question yourself! — jonrsharpe, Nov 19 '14 at 16:02
Here's an elaborate answer: http://stackoverflow.com/questions/18982610/difference-between-except-and-except-exception-as-e-in-python#answer-18982726 — xyres, Nov 19 '14 at 16:18

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

When using except KeyError as e:, you can access the exception and its attributes as an object with e. Like so:

def test_function():
    try:
        do_something_that_fails()
    except Exception as e:
        print e.message, e.args

It will help with debugging any problems you have when the exception is thrown.

You can find more information on how this works in the Python Documentation.

Good luck!

1 Answers1