Hello everyone , I wanted to do a small program which read a txt with fruit's name in each line and then print how many fruits I have of each type. something like these: apple apple and then [(apple,2)] I came up whit this import qualified Data.Map as Map import Data.List import System.IO main = do file <- readFile "fruits.txt" let answer = proccessFile $ lines file putStrLn (show answer) proccessFile :: [String] -> [(String,Int)] proccessFile file = Map.toAscList $ parseFile Map.empty file where parseFile fruits [] = fruits parseFile fruits_map (x:xs) = parseFile (Map.insertWith (+) x 1 fruits_map) xs It works, but I would like to know how would you do it ?, Share different points of view, different code. Was it a good idea to use a Map ?, Did I separate the code in a proper way, I mean pure - impure ? How can we improve the performance ? Best Regards for everyone. Adolfo