Simple Haskell script for word counting
This is just a simple piece of code I put together to play with some Haskell when I realised I've not been writing nearly enough of the stuff.
It reads text from stdin and prints the words it finds together with how many times each one occurred.
It reads text from stdin and prints the words it finds together with how many times each one occurred.
module Main where import List import Control.Arrow type Comparator a = (a -> a -> Ordering) ascending :: (Ord a) => (b -> a) -> Comparator b ascending f x y = compare (f x) (f y) descending :: (Ord a) => (b -> a) -> Comparator b descending = flip . ascending secondary :: Comparator a -> Comparator a -> Comparator a secondary f g x y = case f x y of { EQ -> g x y; z -> z; } -- Returns a list of unique elements together with their frequency. Listed in decreasing order of frequency, followed by increasing order of the elements. count :: (Ord a) => [a] -> [(a, Int)] count = map (head &&& length) . sortBy (descending length `secondary` ascending head) . group . sort main :: IO () main = interact $ unlines . map (\(x, y) -> (take 20 $ x ++ repeat ' ') ++ " : " ++ show y) . count . words
