That discussion on py3k is far from finished. We've also had a similar discussion in the past and ended up with reversed(), which solves the problem on the other end (using a forward slice but iterating backwards).
Also, when I saw your subject I thought rslice() was related to rfind(), so the name is at best questuinable. Let's drop this until we've got clarity on what Py3k actually will do. --Guido On 8/29/06, Nick Coghlan <[EMAIL PROTECTED]> wrote: > A discussion on the py3k list reminded me that translating a forward slice > into a reversed slice is significantly less than obvious to many people. Not > only do you have to negate the step value and swap the start and stop values, > but you also need to subtract one from each of the step values, and ensure the > new start value was actually in the original slice: > > reversed(seq[start:stop:step]) becomes > seq[(stop-1)%abs(step):start-1:-step] > > An rslice builtin would make the latter version significantly easier to read: > > seq[rslice(start, stop, step)] > > Cheers, > Nick. > > -- > Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia > --------------------------------------------------------------- > http://www.boredomandlaziness.org > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/guido%40python.org > -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
