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1. mapMaybeWithKey :: (k -> a -> Maybe b) -> Map k a -> Map k b

   rio	RIO.Map

   Map keys/values and collect the Just results.

   let f k _ = if k < 5 then Just ("key : " ++ (show k)) else Nothing
   mapMaybeWithKey f (fromList [(5,"a"), (3,"b")]) == singleton 3 "key : 3"
   

2. mapMaybeA :: Applicative f => (a -> f (Maybe b)) -> [a] -> f [b]

   rio	RIO.Prelude

   Applicative mapMaybe.

3. mapMaybeM :: Monad m => (a -> m (Maybe b)) -> [a] -> m [b]

   rio	RIO.Prelude

   Monadic mapMaybe.

4. mapMaybeT :: (m (Maybe a) -> n (Maybe b)) -> MaybeT m a -> MaybeT n b

   errors	Control.Error

   Transform the computation inside a MaybeT.

   • runMaybeT (mapMaybeT f m) = f (runMaybeT
     m)

5. mapMaybeT :: (a -> Maybe b) -> [[a]] -> [[b]]

   leancheck	Test.LeanCheck.Tiers

   Like mapMaybe but for tiers.

6. mapMaybeMProp :: (IsList c, IsList d, Eq d, Show d, Show b, Item c ~ a, Item d ~ b, Arbitrary c, Arbitrary b, Show c, Show a, CoArbitrary a, Function a) => Proxy a -> Proxy b -> (forall s . () => (a -> ST s (Maybe b)) -> c -> ST s d) -> Property

   quickcheck-classes-base	Test.QuickCheck.Classes.Base.IsList

   No documentation available.

7. mapMaybeProp :: (IsList c, Item c ~ a, Item d ~ b, Eq d, IsList d, Arbitrary b, Show d, Show b, Arbitrary c, Show c, Show a, Eq c, CoArbitrary a, Function a) => Proxy a -> Proxy b -> ((a -> Maybe b) -> c -> d) -> Property

   quickcheck-classes-base	Test.QuickCheck.Classes.Base.IsList

   Property for the mapMaybe function, which keeps elements for which the predicate holds true.

8. mapMaybeWithKey :: GCompare k2 => (forall (v :: k1) . () => k2 v -> f v -> Maybe (g v)) -> DMap k2 f -> DMap k2 g

   dependent-map	Data.Dependent.Map

   O(n). Map keys/values and collect the Just results.

9. mapMaybeM :: Monad m => (a -> m (Maybe b)) -> [a] -> m [b]

   relude	Relude.Monad.Maybe

   The monadic version of the mapMaybe function.

   >>> :{
   evenInHalf :: Int -> IO (Maybe Int)
   evenInHalf n
   | even n = pure $ Just $ n `div` 2
   | otherwise = pure Nothing
   :}
   

   >>> mapMaybeM evenInHalf [1..10]
   [1,2,3,4,5]
   

10. mapMaybeWithKey :: (k -> v1 -> Maybe v2) -> InsOrdHashMap k v1 -> InsOrdHashMap k v2

    insert-ordered-containers	Data.HashMap.Strict.InsOrd

    No documentation available.

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