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1. mapMaybe :: Ord k => (a -> Maybe b) -> Map k a -> Map k b

   dhall	Dhall.Map

   Transform all values in a Map using the supplied function, deleting the key if the function returns Nothing

   >>> mapMaybe Data.Maybe.listToMaybe (fromList [("C",[1]),("B",[]),("A",[3])])
   fromList [("C",1),("A",3)]
   

2. mapMOf :: LensLike (WrappedMonad m) s t a b -> (a -> m b) -> s -> m t

   dhall	Dhall.Optics

   Identical to Control.Lens.mapMOf

3. mapMaybe :: (a -> Maybe b) -> [a] -> [b]

   foundation	Foundation

   The mapMaybe function is a version of map which can throw out elements. In particular, the functional argument returns something of type Maybe b. If this is Nothing, no element is added on to the result list. If it is Just b, then b is included in the result list.

   Examples

   Using mapMaybe f x is a shortcut for catMaybes $ map f x in most cases:

   >>> import GHC.Internal.Text.Read ( readMaybe )
   
   >>> let readMaybeInt = readMaybe :: String -> Maybe Int
   
   >>> mapMaybe readMaybeInt ["1", "Foo", "3"]
   [1,3]
   
   >>> catMaybes $ map readMaybeInt ["1", "Foo", "3"]
   [1,3]
   

   If we map the Just constructor, the entire list should be returned:

   >>> mapMaybe Just [1,2,3]
   [1,2,3]
   

4. mapM_ :: (Mappable col, Applicative m, Monad m) => (a -> m b) -> col a -> m ()

   foundation	Foundation.Collection

   Evaluate each action in the collection from left to right, and ignore the results. For a version that doesn't ignore the results see sequenceA. sequenceA_ :: (Mappable col, Applicative f) => col (f a) -> f () sequenceA_ col = sequenceA col *> pure () Map each element of a collection to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM.

5. mapM_ :: (Context a, Monad m) => (a -> m b) -> Matrix a -> m ()

   matrices	Data.Matrix

   No documentation available.

6. mapM_ :: forall (v :: Type -> Type) a m b . (Vector v a, Monad m) => (a -> m b) -> Matrix v a -> m ()

   matrices	Data.Matrix.Generic

   No documentation available.

7. mapM_ :: (Context a, Monad m) => (a -> m b) -> Matrix a -> m ()

   matrices	Data.Matrix.Storable

   No documentation available.

8. mapM_ :: (Context a, Monad m) => (a -> m b) -> Matrix a -> m ()

   matrices	Data.Matrix.Unboxed

   No documentation available.

9. mapMaybe :: (a -> Maybe b) -> MonoidalIntMap a -> MonoidalIntMap b

   monoidal-containers	Data.IntMap.Monoidal

   No documentation available.

10. mapMaybeWithKey :: (Int -> a -> Maybe b) -> MonoidalIntMap a -> MonoidalIntMap b

    monoidal-containers	Data.IntMap.Monoidal

    No documentation available.

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