On 1/20/07, Kent Johnson <[EMAIL PROTECTED]> wrote: > Adam Cripps wrote: > > On 1/19/07, Simon Brunning <[EMAIL PROTECTED]> wrote: > >> On 1/19/07, Adam Cripps <[EMAIL PROTECTED]> wrote: > >>> I'm adding strings to a Set to prevent duplicates. However, the > >>> strings are meant to be in the correct order. When I add the string to > >>> the Set, the order seems to change (and I don't seem to be able to > >>> predict what order they are in). > >> Sets, like dictionaries, hold their items in an arbitrary order - see > >> <http://tinyurl.com/a2nkg>. > > > > OK - thanks for that - so it seems that using a Set will complicate > > the matter more. > > > > Really, I want to have a set of sets which won't have any duplicates. > > An example might look something ilke this: > > > > sums = [['1) 10 + 2 =', '12'], ['2) 13 + 4 =', '17']] > > return sums > > > > How might I achieve this list, without the duplicates (the duplicate > > bit is the bit I'm stuck on). > > What is your criterion for uniqueness? Are you looking at just the sum, > as you mentioned earlier, or the whole problem? Why is the order > important, since the problems are randomly generated? > > You should think about a more abstract way of representing a problem. > For example, the two problems above could be represented as the tuples > (10, 2, 12) and (13, 4, 17). If you want the whole problems to be > unique, then creating a set of tuples like this should do what you want. > (I used tuples instead of lists because you can't make a set of lists.) > > If you want only one problem with a given sum, then I would represent a > problem as an entry in a dictionary where the sum is the key and the > value is a tuple containing the two addends. Then you can keep putting > problems in the dictionary until it is the size you want. > > Once you have the final set (or dict) of problems, then you can convert > them to a string representation and print them.
Many thanks all - I've got there in the end, using a tuple inside a set, ditching the question number and then rendering the sum for output in my main gui module. However, this does raise another issue now (which I had thought would happen, but was putting it off until I'd solved the original problem). Basically, the user can choose how many problems are set - i. They can also choose the highest and lowest possible numbers - highest and lowest. With these values, they can now create a scenario which will lock the application - they can choose values with a narrow margin (lowest = 5, highest = 6) and then choose to have 100 of these problems (i=100). Of course, this will mean that my app will now go through that loop trying to find a new combination that no longer is possible. Anyone have any guidance or tips here? How will I create a flag which is raised once the loop becomes infinite? TIA Adam -- http://www.monkeez.org PGP key: 0x7111B833 _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
