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  1. mapMaybe :: forall (m :: Type -> Type) a b r . Monad m => (a -> Maybe b) -> Fold m b r -> Fold m a r

    streamly-core Streamly.Data.Fold

    mapMaybe f fold maps a Maybe returning function f on the input of the fold, filters out Nothing elements, and return the values extracted from Just. 

    >>> mapMaybe f = Fold.lmap f . Fold.catMaybes

>>> mapMaybe f = Fold.mapMaybeM (return . f)

    >>> f x = if even x then Just x else Nothing

>>> fld = Fold.mapMaybe f Fold.toList

>>> Stream.fold fld (Stream.enumerateFromTo 1 10)
[2,4,6,8,10]

  2. mapMaybe :: forall (m :: Type -> Type) a b . Monad m => (a -> Maybe b) -> Stream m a -> Stream m b

    streamly-core Streamly.Data.Stream

    Map a Maybe returning function to a stream, filter out the Nothing elements, and return a stream of values extracted from Just. Equivalent to: 

    >>> mapMaybe f = Stream.catMaybes . fmap f

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

    streamly-core Streamly.Data.Stream

    Like mapMaybe but maps a monadic function. Equivalent to: 

    >>> mapMaybeM f = Stream.catMaybes . Stream.mapM f

    >>> mapM f = Stream.mapMaybeM (\x -> Just <$> f x)

  4. mapMStep :: Applicative m => (a -> m b) -> Step s a -> m (Step s b)

    streamly-core Streamly.Internal.Data.Fold

    Map a monadic function over the result b in Step s b. Internal

  5. mapMaybe :: forall (m :: Type -> Type) a b r . Monad m => (a -> Maybe b) -> Fold m b r -> Fold m a r

    streamly-core Streamly.Internal.Data.Fold

    mapMaybe f fold maps a Maybe returning function f on the input of the fold, filters out Nothing elements, and return the values extracted from Just. 

    >>> mapMaybe f = Fold.lmap f . Fold.catMaybes

>>> mapMaybe f = Fold.mapMaybeM (return . f)

    >>> f x = if even x then Just x else Nothing

>>> fld = Fold.mapMaybe f Fold.toList

>>> Stream.fold fld (Stream.enumerateFromTo 1 10)
[2,4,6,8,10]

  6. mapMaybeM :: Monad m => (a -> m (Maybe b)) -> Fold m b r -> Fold m a r

    streamly-core Streamly.Internal.Data.Fold 

    >>> mapMaybeM f = Fold.lmapM f . Fold.catMaybes

  7. mapM_ :: Monad m => (a -> m b) -> Stream m a -> m ()

    streamly-core Streamly.Internal.Data.Stream

    Execute a monadic action for each element of the Stream

  8. mapMaybe :: forall (m :: Type -> Type) a b . Monad m => (a -> Maybe b) -> Stream m a -> Stream m b

    streamly-core Streamly.Internal.Data.Stream

    Map a Maybe returning function to a stream, filter out the Nothing elements, and return a stream of values extracted from Just. Equivalent to: 

    >>> mapMaybe f = Stream.catMaybes . fmap f

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

    streamly-core Streamly.Internal.Data.Stream

    Like mapMaybe but maps a monadic function. Equivalent to: 

    >>> mapMaybeM f = Stream.catMaybes . Stream.mapM f

    >>> mapM f = Stream.mapMaybeM (\x -> Just <$> f x)

  10. mapMSerial :: Monad m => (a -> m b) -> StreamK m a -> StreamK m b

    streamly-core Streamly.Internal.Data.StreamK

    No documentation available.

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