On Tue, 29 Aug 2006 17:44:40 +0100, David Hopwood <[EMAIL PROTECTED]> wrote: >Nick Coghlan 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)] > >Or slice.reversed(). >
Better, slice.reversed(length). Jean-Paul _______________________________________________ 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
