Data commit

Task/Averages-Arithmetic-mean/Haskell/averages-arithmetic-mean-1.hs

@@ -0,0 +1,3 @@
+mean :: (Fractional a) => [a] -> a
+mean [] = 0
+mean xs = sum xs / Data.List.genericLength xs

Task/Averages-Arithmetic-mean/Haskell/averages-arithmetic-mean-2.hs

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+meanReals :: (Real a, Fractional b) => [a] -> b
+meanReals = mean . map realToFrac

Task/Averages-Arithmetic-mean/Haskell/averages-arithmetic-mean-3.hs

@@ -0,0 +1,19 @@
+{-# LANGUAGE BangPatterns #-}
+
+import Data.List (foldl') --'
+
+mean
+  :: (Real n, Fractional m)
+  => [n] -> m
+mean xs =
+  let (s, l) =
+        foldl' --'
+          f
+          (0, 0)
+          xs
+  in realToFrac s / l
+  where
+    f (!s, !l) x = (s + x, l + 1)
+
+main :: IO ()
+main = print $ mean [1 .. 100]