On Mon, Oct 12, 2009 at 10:09 AM, kevin parks <k...@mac.com> wrote: >> > I don't understand why you want to flatten outlist; when I run your >> > program I get one number per line, not one generation per line as you >> > show above. > > > That's odd. Anyway in my program I am printing the list twice. The first > time outlist is printed it is nested one level deep. That is just > scaffolding. Then i pick through it one item per line having flattened it > and print it in a format that my other program can read.
In the program you posted, outlist is a list of lists where each sub-list is a list of integers representing one generation of the automaton. When outlist is flattened, the result is a single list of integers. Maybe what you posted and what you tried are different? > I been using that flatten function since 1970. Prolly pilfered from Tim > Peters or Effbot. Remember them guys? Awesome dudes. I wonder if they even > use python anymore. Yes; Tim Peters lurks on this list; Fredrik Lundh still maintains PIL, at least. > Anyway that is from way before itertools was even a > glimmer. Additionally, your flatten function doesn't work for me actually. I > get: > > NameError: global name 'chain' is not defined from itertools import chain >> > I don't think you will get an infinite loop. You may have a grammar >> > that generates a stable or repeating pattern but I don't think you >> > will be able to detect that without trying it. > > Yeah i don't mean an infinite loop, but more like a perpetual dance back and > forth between to items > that point to each other. I think I need to be careful when i define the > rules that i don't get something like that... say if 1 goes to 4 but 4's > rule is go to 1, for example. That can clearly happen. There are several cases: - every rule maps to a single symbol. In this case, each generation is the same size as the previous generation and the pattern must repeat at some point, as the number of patterns is limited - all rules map to more than one symbol. In this case each generation is longer than the previous so there can not be a repeat. - at least one rule, but not all, maps to more than one symbol. In this case either outcome is possible, depending on whether the expanding rule is repeatedly hit. Kent _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
