mapAccumWithKey

mapAccumWithKey :: (a -> Key -> b -> (a, c)) -> a -> IntMap b -> (a, IntMap c)
containers Data.IntMap.Strict, containers Data.IntMap.Lazy
O(n). The function mapAccumWithKey threads an accumulating argument through the map in ascending order of keys. > let f a k b = (a ++ " " ++ (show k) ++ "-" ++ b, b ++ "X") > mapAccumWithKey f "Everything:" (fromList [(5,"a"), (3,"b")]) == ("Everything: 3-b 5-a", fromList [(3, "bX"), (5, "aX")])
mapAccumWithKey :: (a -> k -> b -> (a, c)) -> a -> Map k b -> (a, Map k c)
containers Data.Map.Lazy, containers Data.Map.Strict
O(n). The function mapAccumWithKey threads an accumulating argument through the map in ascending order of keys. > let f a k b = (a ++ " " ++ (show k) ++ "-" ++ b, b ++ "X") > mapAccumWithKey f "Everything:" (fromList [(5,"a"), (3,"b")]) == ("Everything: 3-b 5-a", fromList [(3, "bX"), (5, "aX")])