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Purpose of else and finally in exception handling

I’d like to understand why the finally clause exists in the try/except statement. I understand what it does, but clearly I’m missing something if it deserves a place in the language. Concretely, what’s the difference between writing a clause in the finally field with respect of writing it outside the try/except statement?

Answer 1

The finally suite is guaranteed to be executed, whatever happens in the try suite.

Use it to clean up files, database connections, etc:

try:
    file = open('frobnaz.txt', 'w')
    raise ValueError
finally:
    file.close()
    os.path.remove('frobnaz.txt')

This is true regardless of whether an exception handler (except suite) catches the exception or not, or if there is a return statement in your code:

def foobar():
    try:
        return
    finally:
        print "finally is executed before we return!"

Using a try/finally statement in a loop, then breaking out of the loop with either continue or break would, again, execute the finally suite. It is guaranteed to be executed in all cases.