Lorenzo,
On Sun, Oct 10, 2010 at 4:15 PM, Lorenzo Isella
... In order to find the length of the longest list in the future which has already been seen in the past, I could select the "true" values in the output of function
iter_find list i
but this is a waste of CPU: I simply would like a while condition to tell my function to stop checking new sublists as soon as it finds one which has not occurred in the past and I would like a counter (a kind of i++) telling me how many times the process has been iterated.
I'm still a beginner myself, but here's my take on it. Since Haskell is lazy, the results will only be generated as they are needed. For example, if you change: let b = iter_find list i for let b = takeWhile id $ iter_find list i Haskell will stop generating the list as soon as it sees a False result. Then you can take the length of b as your answer. Patrick
Any suggestion is helpful. Cheers
Lorenzo
-------------------------------------------------------------------
import Data.Ord
import Data.List
main :: IO ()
main = do
let list = [4,55,66,77,88,99,12,9,77,88,99,12,-99]
let i = 9
let b = iter_find list i
putStrLn "b is, " print b
is_sublist sublist list = sublist `isInfixOf` list
gen_fut_list list i j = take j $ drop (i-1) list
gen_past_list list i = take (i-1) list
find_in_list list i j = is_sublist (gen_fut_list list i j) (gen_past_list list i)
iter_find list i = map (find_in_list list i) [1..n] where n = (length list) - i +1
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-- ===================== Patrick LeBoutillier Rosemère, Québec, Canada