RosettaCodeData/Task/Text-processing-2/Haskell/text-processing-2.hs

19 lines
638 B
Haskell

import Data.List (nub, (\\))
data Record = Record {date :: String, recs :: [(Double, Int)]}
duplicatedDates rs = rs \\ nub rs
goodRecords = filter ((== 24) . length . filter ((>= 1) . snd) . recs)
parseLine l = let ws = words l in Record (head ws) (mapRecords (tail ws))
mapRecords [] = []
mapRecords [_] = error "invalid data"
mapRecords (value:flag:tail) = (read value, read flag) : mapRecords tail
main = do
inputs <- (map parseLine . lines) `fmap` readFile "readings.txt"
putStr (unlines ("duplicated dates:": duplicatedDates (map date inputs)))
putStrLn ("number of good records: " ++ show (length $ goodRecords inputs))