On Feb 9, 11:10 am, "Diez B. Roggisch" <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] schrieb: > > > i'm having trouble trying to figure this out... it's part of a build > > system i'm writing in python. maybe someone has a good simple way to > > solve this. i'm trying to create a dependency order out of multiple > > lists. > > > list1: B C > > list2: A B > > list3: A C > > > i want the end result to be the list: A B C > > i'm very frustrated that i can't come up with anything that always > > works. > > > thanks... any clues to solve this would be greatly appreciated. > > Maybe the frustration is based on the IMHO wrong data-structure you use. > What does [B, C] mean? > > A common approach for this is to create a dict instead, that maps an > object to the list of things it depends on (or that depend on it, it's > essentially the same) > > The resulting data-structure is called a directed graph, and there are > algorithms like "partial orderings" you can google for that will help you. > > An example graph would be: > > dict( > "A" : ["B", "C"], > "B" : ["C"] > "C" : [] > ) > > Then the result of a partial ordering would be > > ["C", "B", "A"] > > which should be what you are after. > > Diez
i found this program in pypi, it does exactly what i was after :) http://pypi.python.org/pypi/topsort/0.9 >>> from topsort import topsort >>> topsort([('B', 'C'),('A', 'B'),('A', 'C')]) ['A', 'B', 'C'] very cool!!! i will be able to adapt this to my program without any problems. -- http://mail.python.org/mailman/listinfo/python-list
