
Re: sorting?
Posted:
Jan 28, 2013 2:23 AM


Many thanks Bob!
Francisco
________________________________ From: Bob Hanlon <hanlonr357@gmail.com> Sent: Saturday, January 26, 2013 4:58 PM Subject: Re: sorting?
lalista = {{0, 5}, {8, 8}, {2, 2}, {3, 5}, {1, 3}, {3, 9}};
SortBy[lalista, (Divide @@ #) + 10^6*#[[2]] &] // Reverse
{{8, 8}, {2, 2}, {3, 5}, {3, 9}, {1, 3}, {0, 5}}
Bob Hanlon
On Sat, Jan 26, 2013 at 1:39 AM, Francisco Gutierrez <fgutiers2002@yahoo.com> wrote:
> > Friends: > I have a large list of simple numerical lists, and I want to sort it using two criteria. in the simplest case, suppose the sublists are of length two, and > that my first criterion is the quotient of part one by part two, and my second criterion is the size of part two (no zeros in part 2. I want to sort > using the first criterion, and then break the ties using the second one. > So for example if I had > lalista={{0,5},{8,8},{2,2},{3,5},{1,3},{3,9}}, > the sorting should return > {8,8},{2,2},{3,5},{3,9},{1,3},{0,5}} > > Of course this can be done, but I wonder if it is a way to make this only with native Mathematica tools (wich is always far more efficient).
> Thanks for your help > Francisco >

