On Sunday, 7 October 2012 01:12:56 UTC+5:30, Terry Reedy wrote: > On 10/6/2012 7:36 AM, Dave Angel wrote: > > > > > The distinction in performance between the success and failure modes of > > > the try/catch isn't nearly as large as one of the other responses might > > > lead you to believe. For example, a for loop generally terminates with > > > a raise (of StopIteration exception), and that doesn't convince us to > > > replace it with a while loop. > > > > For statement generally loop many times, up to millions of times, > > without an exception being raised, whereas while statements test the > > condition each time around the loop. So the rule 'if failure is rare > > (less than 10-20%) use try', applies here. For if/them versus > > try/except, I don't worry too much about it. > > > > -- > > Terry Jan Reedy
I use try and except when I need to raise exceptions e.g.: try: value = vm.variables[name] except KeyError: raise NameError("variable name not defined in VM's variables") -- http://mail.python.org/mailman/listinfo/python-list