Lasse Vågsæther Karlsen wrote: > I have a list of items and a "rule" for ordering them. > > Unfortunately, the rule is not complete so it won't define the correct > order for any two items in that list.
This is called a "partial ordering". [...] > If there isn't anything built in, does anyone have an idea about how to > go about creating such an ordering function ? Tweaking a cmp-like > function to return 0 for "undefined" didn't seem to work so there must > be a slightly more intelligent solution than that. Perhaps the rules > would have to be checked in a specific order. The usual tools to deal with partial orderings are directed acyclic graphs, and "topological sorting". Try Googling the terms along with "Python". -- --Bryan -- http://mail.python.org/mailman/listinfo/python-list
