null -package:base

null :: ByteString -> Bool
bytestring Data.ByteString Data.ByteString.Char8 Data.ByteString.Lazy Data.ByteString.Lazy.Char8
O(1) Test whether a ByteString is empty.
null :: ShortByteString -> Bool
bytestring Data.ByteString.Short Data.ByteString.Short.Internal
O(1) Test whether a ShortByteString is empty.
null :: Text -> Bool
text Data.Text Data.Text.Lazy
O(1) Tests whether a Text is empty or not.
null :: Stream Char -> Bool
text Data.Text.Internal.Fusion.Common
O(1) Tests whether a Stream Char is empty or not. Properties 
null . stream = null
null :: IntMap a -> Bool
containers Data.IntMap.Internal Data.IntMap.Lazy Data.IntMap.Strict Data.IntMap.Strict.Internal
Is the map empty? 
Data.IntMap.null (empty)           == True
Data.IntMap.null (singleton 1 'a') == False
null :: IntSet -> Bool
containers Data.IntSet Data.IntSet.Internal
Is the set empty?
null :: Map k a -> Bool
containers Data.Map.Internal Data.Map.Lazy Data.Map.Strict Data.Map.Strict.Internal
Is the map empty? 
Data.Map.null (empty)           == True
Data.Map.null (singleton 1 'a') == False
null :: Seq a -> Bool
containers Data.Sequence Data.Sequence.Internal
Is this the empty sequence?
null :: Set a -> Bool
containers Data.Set Data.Set.Internal
Is this the empty set?
null :: KeyMap v -> Bool
aeson Data.Aeson.KeyMap
Is the map empty?
null :: Vector a -> Bool
vector Data.Vector Data.Vector.Strict
O(1) Test whether a vector is empty.
null :: forall (v :: Type -> Type) a . Bundle v a -> Bool
vector Data.Vector.Fusion.Bundle
Check if a Bundle is empty
null :: forall m (v :: Type -> Type) a . Monad m => Bundle m v a -> m Bool
vector Data.Vector.Fusion.Bundle.Monadic
Check if a Bundle is empty
null :: Monad m => Stream m a -> m Bool
vector Data.Vector.Fusion.Stream.Monadic
null :: Vector v a => v a -> Bool
vector Data.Vector.Generic
O(1) Test whether a vector is empty.
null :: MVector v a => v s a -> Bool
vector Data.Vector.Generic.Mutable
Check whether the vector is empty.
null :: MVector s a -> Bool
vector Data.Vector.Mutable Data.Vector.Strict.Mutable
Check whether the vector is empty.
null :: Prim a => Vector a -> Bool
vector Data.Vector.Primitive
O(1) Test whether a vector is empty.
null :: Prim a => MVector s a -> Bool
vector Data.Vector.Primitive.Mutable
Check whether the vector is empty.
null :: Storable a => Vector a -> Bool
vector Data.Vector.Storable
O(1) Test whether a vector is empty.
null :: Storable a => MVector s a -> Bool
vector Data.Vector.Storable.Mutable
Check whether the vector is empty.
null :: Unbox a => Vector a -> Bool
vector Data.Vector.Unboxed
O(1) Test whether a vector is empty.
null :: Unbox a => MVector s a -> Bool
vector Data.Vector.Unboxed.Mutable
Check whether the vector is empty.
null :: HashMap k v -> Bool
unordered-containers Data.HashMap.Internal Data.HashMap.Internal.Strict Data.HashMap.Lazy Data.HashMap.Strict
Return True if this map is empty, False otherwise.
null :: HashSet a -> Bool
unordered-containers Data.HashSet
Return True if this set is empty, False otherwise. 
>>> HashSet.null HashSet.empty
True

>>> HashSet.null (HashSet.singleton 1)
False