Question

Problem with a recursive approach to problem set 2 question 2 (ps3b).

Answer 1

I always end up with the function yielding nested tuples, plus I could not do it without passing an additional arg. to the function to keep the length of the sliced string.
http://dpaste.com/531825/
Any ideas?

Answer 2

Sorry, this question is in regards to problem set 3, not 2

Answer 3

I don't understand recursive functions enough to explain them but I can give you mine if you want it and you can try to figure it out?

Answer 4

that'll be great, thanks

Answer 5

http://dpaste.com/hold/531832/

Answer 6

to solve the nested tuple problem, instead of returning loc, subStringMatchRecursive(target,key,(loc+1))
you return things like
loc + subStringMatchRecursive(target,key,(loc+1))
when you use a comma, even without parens it assumes your trying to make a tuple, or at least it does sometimes, its sketchy at best.
when you use the "+", tried to create one whole thing.
sometimes the tuple doesn't like to add with a non tuple, when that happens i find that you can help it along by putting the non tuple variable (say x)
tuple + (x,)
hopefully that made sense and i understood what was going wrong

Answer 7

Like Nessman said, you can fix your code by returning:
(loc,) + subStringMatchRecursive(target,key,(loc+1))

You'll also have to seed an empty tuple instead of None, which is what you're implicitly seeding (by not having a return outside the while loop). You can do that by adding "return tuple()" outside your while loop.

I've attached my ps3b.py for reference. I solved it three different ways, but my "subStringMatchExact2" is closest to your code.