RosettaCodeData/Task/Entropy/Haskell/entropy.hs

import Data.List

main = print $ entropy "1223334444"

entropy :: (Ord a, Floating c) => [a] -> c
entropy = sum . map lg . fq . map genericLength . group . sort
  where lg c = -c * logBase 2 c
        fq c = let sc = sum c in map (/ sc) c
First commit of partial RosettaCode contents. Pushing this for testing purposes. Lots of work still needed. 2013-04-08 13:02:41 -07:00			`import Data.List`

			`main = print $ entropy "1223334444"`

2016 Update 2016-12-05 22:15:40 +01:00			`entropy :: (Ord a, Floating c) => [a] -> c`
			`entropy = sum . map lg . fq . map genericLength . group . sort`
			`where lg c = -c * logBase 2 c`
			`fq c = let sc = sum c in map (/ sc) c`