Haskell Hack

gistfile1.txt

import Data.Char
import Data.Maybe
import Data.List
import Data.Map hiding (map)
import Text.Printf

main = do
        src <- readFile "grades.txt"
        let pairs   = map (split.words) (lines src)
        let grades  = foldr insert empty pairs
        mapM_ (draw grades) (sort (keys grades))
      where
        insert (s, g) = insertWith (++) s [g]
        split [name,mark] = (name, read mark)

        draw g s = printf "%s\t%s\tAverage: %f\n" s (show marks) avg
          where
            marks = findWithDefault (error "No such student") s g
            avg   = sum marks / fromIntegral (length marks) :: Double