How about this one? Should be pretty efficient.
let mavg n xs = let (sum -> seed,rest) = splitAt n xs in map (%n) .
scanl (\a (p,n) -> a+n-p) seed $ xs `zip` rest
2009/8/27 Patai Gergely
For example, starting from
[4,3,2,6,7]
you need to find the averages of
4,3,2 and 3,2,6 and 2,6,7
resulting in
[3,4,5]
What is the most elegant way to do that? It's probably less elegant than tails, but very likely more efficient to keep track of running sums instead of summing the sublists over and over again.
import Data.Ratio
nsums n xs = map (% n) $ scanl (+) (sum (take n xs)) $ zipWith (-) (drop n xs) xs
Gergely
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