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

   rio	RIO.Map

   Map values and collect the Just results.

   let f x = if x == "a" then Just "new a" else Nothing
   mapMaybe f (fromList [(5,"a"), (3,"b")]) == singleton 5 "new a"
   

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

   rio	RIO.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]
   

3. mapMaybe :: (Vector v a, Vector v b) => (a -> Maybe b) -> v a -> v b

   rio	RIO.Vector

   No documentation available.

4. mapMaybe :: (a -> Maybe b) -> Vector a -> Vector b

   rio	RIO.Vector.Boxed

   No documentation available.

5. mapMaybe :: (Storable a, Storable b) => (a -> Maybe b) -> Vector a -> Vector b

   rio	RIO.Vector.Storable

   No documentation available.

6. mapMaybe :: (Unbox a, Unbox b) => (a -> Maybe b) -> Vector a -> Vector b

   rio	RIO.Vector.Unboxed

   No documentation available.

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

   errors	Control.Error

   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]
   

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

   Cabal-syntax	Distribution.Compat.Prelude

   No documentation available.

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

   relude	Relude.Monad.Reexport

   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]
   

10. mapMaybe :: Ord key => key -> Accessor (Map key elem) (Maybe elem)

    distributed-process	Control.Distributed.Process.Internal.StrictContainerAccessors

    No documentation available.

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