2023-06-30 19:54 UTC+02:00, MRAB <pyt...@mrabarnett.plus.com>: > On 2023-06-30 14:55, Daniel Walker wrote: >> As most of you probably know, you can use else with try blocks: >> >> try: >> do_stuff() >> except SomeExceptionClass: >> handle_error() >> else: >> no_error_occurred() >> >> Here, no_error_occurred will only be called if do_stuff() didn't raise >> an exception. >> >> However, the following is invalid syntax: >> >> try: >> do_stuff() >> else: >> no_error_occurred() >> >> Now you might say that this isn't needed as you can achieve the same >> result with >> >> do_stuff() >> no_error_occurred() >> >> However, what if I want to use finally as well: >> >> try: >> do_stuff() >> else: >> no_error_occurred() >> finally: >> cleanup() >> >> and I need no_error_occurred to be called before cleanup? For my actual >> use case, I've done >> >> try: >> do_stuff() >> except Exception: >> raise >> else: >> no_error_occurred() >> finally: >> cleanup() >> >> This seems very non-Pythonic. Is there a reason why else without except >> has to be invalid syntax? >> > What would be the difference between > > try: > do_stuff() > else: > no_error_occurred() > finally: > cleanup() > > and > > try: > do_stuff() > no_error_occurred() > finally: > cleanup() > > ? >
One could argue that it's conceptually not the same although the actual execution is the same. In the first case you intend to only catch the exceptions generated by do_stuff(). In the second case, you intend to catch those generated by do_stuff() and those generated by no_error_occurred(). If later on an "except" is added, the developper doing the modification should be reminded to move the call to no_error_occurred() into an "else". With real-world non-trivial code, it might not be so simple to see. I'm not an expert, but I actually see no downside to having an "else" without an "except". Best regards, Celelibi _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/ROEHA53I2LV6PIR32ZAGAWTK6SEV5CBJ/ Code of Conduct: http://python.org/psf/codeofconduct/
