New submission from fabrice salvaire <fabrice.salva...@orange.fr>:
I just implemented Graham Scan algorithm in Python 3 and have to read carefully the sort documentation. Notice this is a good algorithm for a large audience language like Python. Since Python 3, the old order function cmp is depicted as an old way to proceed. But some sorting procedure require complex order like this def sort_by_y(p0, p1): return p0.x - p1.x if (p0.y == p1.y) else p0.y - p1.y sorted(points, key=cmp_to_key(sort_by_y)) which is less natural to implement than def sort_by_y(p0, p1): return p0.x < p1.x if (p0.y == p1.y) else p0.y < p1.y sorted(points, cmp=sort_by_y) Since Python 3 we should do this points.sort(key=attrgetter('x')) points.sort(key=attrgetter('y')) But we must take care to the chaining order !!! Here we must sort first on x then on y. I think the documentation could explain much better how to perform complex sort and the performance of the Python sort algorithm. Is the old way faster than the new one ??? What about short and large array ??? What happen when we sort a zillion of short array ??? ---------- assignee: docs@python components: Documentation messages: 335163 nosy: FabriceSalvaire, docs@python priority: normal severity: normal status: open title: Sort documentation could be improved for complex sorting type: enhancement versions: Python 3.7 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue35956> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com