1 files changed, 17 insertions, 0 deletions
diff --git a/src/client/Utils/List.elm b/src/client/Utils/List.elm
new file mode 100644
index 0000000..cc57d9f
--- /dev/null
+++ b/src/client/Utils/List.elm
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+module Utils.List exposing
+  ( groupBy
+  , mean
+  )
+
+import Dict
+
+groupBy : (a -> comparable) -> List a -> List (comparable, List a)
+groupBy f xs =
+  let addItem item dict =
+        let groupItems = Dict.get (f item) dict |> Maybe.withDefault []
+        in  Dict.insert (f item) (item :: groupItems) dict
+  in  List.foldr addItem Dict.empty xs
+        |> Dict.toList
+
+mean : List Int -> Int
+mean xs = (List.sum xs) // (List.length xs)