What is the intended use of the optional "else" clause of the "try" statement in Python?
exception, python
Solution
The statements in the `else` block are executed if execution falls off the bottom of the `try` - if there was no exception. Honestly, I've never found a need.
However, Handling Exceptions notes:
The use of the else clause is better than adding additional code to the try clause because it avoids accidentally catching an exception that wasn’t raised by the code being protected by the try ... except statement.
So, if you have a method that could, for example, throw an `IOError`, and you want to catch exceptions it raises, but there's something else you want to do if the first operation succeeds, and you don't want to catch an IOError from that operation, you might write something like this:
try:
operation_that_can_throw_ioerror()
except IOError:
handle_the_exception_somehow()
else:
# we don't want to catch the IOError if it's raised
another_operation_that_can_throw_ioerror()
finally:
something_we_always_need_to_do()
If you just put `another_operation_that_can_throw_ioerror()` after `operation_that_can_throw_ioerror`, the `except` would catch the second call's errors. And if you put it after the whole `try` block, it'll always be run, and not until after the `finally`. The `else` lets you make sure
- the second operation's only run if there's no exception,
- it's run before the `finally` block, and
- any `IOError`s it raises aren't caught here
Problem
What is the intended use of the optional `else` clause of the `try` statement?