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1. mapM_ :: Monad m => (a -> m b) -> NonEmptyVector a -> m ()

   nonempty-vector	Data.Vector.NonEmpty

   O(n) Apply the monadic action to all elements of a non-empty vector and ignore the results.

   >>> mapM_ (const $ Just ()) (unsafeFromList [1..3])
   Just ()
   

   >>> mapM_ (const Nothing) (unsafeFromList [1..3])
   Nothing
   

2. mapMaybe :: (a -> Maybe b) -> NonEmptyVector a -> Vector b

   nonempty-vector	Data.Vector.NonEmpty

   O(n) Drop elements when predicate returns Nothing If no elements satisfy the predicate, the resulting vector may be empty.

   >>> mapMaybe (\a -> if a == 2 then Nothing else Just a) (unsafeFromList [1..3])
   [1,3]
   

3. mapMLazy :: PrimBase m => (a -> m b) -> [a] -> m [b]

   simple-cairo	Graphics.Cairo.Drawing.CairoPatternT.Mesh

   No documentation available.

4. mapMaybeReversed :: (a -> Maybe b) -> List a -> List b

   strict-list	StrictList

   Map and filter elements producing results in reversed order.

5. mapM_ :: (Foldable t, Monad m) => (a -> m ()) -> t a -> m ()

   LambdaHack	Game.LambdaHack.Core.Prelude

   This has a more specific type (unit result) than normally, to catch errors.

6. mapMaybe :: List l => (a -> Maybe b) -> l a -> l b

   List	Data.List.Class

   No documentation available.

7. mapMaybe :: (a -> Maybe b) -> Trie a -> Maybe (Trie b)

   bcp47	Data.BCP47.Trie

   No documentation available.

8. mapMaybe :: (a -> Maybe b) -> Trie a -> Maybe (Trie b)

   bcp47	Data.BCP47.Trie.Internal

   No documentation available.

9. mapMaybe2 :: (a -> Maybe b) -> Trie2 a -> Maybe (Trie2 b)

   bcp47	Data.BCP47.Trie.Internal

   No documentation available.

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

    cabal-install-solver	Distribution.Solver.Compat.Prelude

    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]
    

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