On Tue, 26 Jan 2010 02:00:34 -0800 (PST), Dima Pasechnik <dimp...@gmail.com> wrote: > yes, this works for numerical lists, but not for e.g. > [[1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, -1, -1, -1], [2, -1, 2, -1, > 2, 0, 0, 0], [2, 1, -2, -1, 0, -zeta8^3 - zeta8, zeta8^3 + zeta8, 0], > [2, 1, -2, -1, 0, zeta8^3 + zeta8, -zeta8^3 - zeta8, 0], [3, 0, 3, 0, > -1, 1, 1, -1], [3, 0, 3, 0, -1, -1, -1, 1], [4, -1, -4, 1, 0, 0, 0, > 0]] > > (sorted does not like mixing zeta (string(?)) with numbers, > apparently) >
Here is what I get: sage: K.<zeta8> = CyclotomicField(8) sage: lst = [[1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 1, -1, -1, -1], [2, -1, 2, -1, 2, 0, 0, 0], [2, 1, -2, -1, 0, -zeta8^3 - zeta8, zeta8^3 + zeta8, 0], [2, 1, -2, -1, 0, zeta8^3 + zeta8, -zeta8^3 - zeta8, 0], [3, 0, 3, 0, -1, 1, 1, -1], [3, 0, 3, 0, -1, -1, -1, 1], [4, -1, -4, 1, 0, 0, 0, 0]] sage: sorted(lst) [[1, 1, 1, 1, 1, -1, -1, -1], [1, 1, 1, 1, 1, 1, 1, 1], [2, -1, 2, -1, 2, 0, 0, 0], [2, 1, -2, -1, 0, -zeta8^3 - zeta8, zeta8^3 + zeta8, 0], [2, 1, -2, -1, 0, zeta8^3 + zeta8, -zeta8^3 - zeta8, 0], [3, 0, 3, 0, -1, -1, -1, 1], [3, 0, 3, 0, -1, 1, 1, -1], [4, -1, -4, 1, 0, 0, 0, 0]] I'm not sure what you mean by "works" or "does not work". The list gets sorted by Python. This ordering does not magically acquire mathematical naturality that it did not have before, we just get a list that will now be the same no matter what version of Sage, GAP, C compiler, etc. is used. The only way you might be able to get a different-looking result now is if you change the underlying comparison function, which is not something that happens very often at all. So the point of sorted() is not necessarily that the resulting list will look sorted to the human eye, but that computers will reliably always get the same answer. Best, Alex -- Alex Ghitza -- Lecturer in Mathematics -- The University of Melbourne -- Australia -- http://www.ms.unimelb.edu.au/~aghitza/ -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
