Data.HashSet

A set of hashable values. A set cannot contain duplicate items. A HashSet makes no guarantees as to the order of its elements.

The implementation is based on hash array mapped trie. A HashSet is often faster than other tree-based set types, especially when value comparison is expensive, as in the case of strings.

Many operations have a average-case complexity of O(log n). The implementation uses a large base (i.e. 16) so in practice these operations are constant time.

Documentation

data HashSet a

A set of values. A set cannot contain duplicate values.

Instances

Foldable HashSet

Methods

fold :: Monoid m => HashSet m -> m

foldMap :: Monoid m => (a -> m) -> HashSet a -> m

foldr :: (a -> b -> b) -> b -> HashSet a -> b

foldr' :: (a -> b -> b) -> b -> HashSet a -> b

foldl :: (b -> a -> b) -> b -> HashSet a -> b

foldl' :: (b -> a -> b) -> b -> HashSet a -> b

foldr1 :: (a -> a -> a) -> HashSet a -> a

foldl1 :: (a -> a -> a) -> HashSet a -> a

toList :: HashSet a -> [a]

null :: HashSet a -> Bool

length :: HashSet a -> Int

elem :: Eq a => a -> HashSet a -> Bool

maximum :: Ord a => HashSet a -> a

minimum :: Ord a => HashSet a -> a

sum :: Num a => HashSet a -> a

product :: Num a => HashSet a -> a

Eq1 HashSet

Methods

liftEq :: (a -> b -> Bool) -> HashSet a -> HashSet b -> Bool

Ord1 HashSet

Methods

liftCompare :: (a -> b -> Ordering) -> HashSet a -> HashSet b -> Ordering

Show1 HashSet

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> HashSet a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [HashSet a] -> ShowS

Hashable1 HashSet

Methods

liftHashWithSalt :: (Int -> a -> Int) -> Int -> HashSet a -> Int

(Eq a, Hashable a) => IsList (HashSet a)

Associated Types

type Item (HashSet a) :: *

Methods

fromList :: [Item (HashSet a)] -> HashSet a

fromListN :: Int -> [Item (HashSet a)] -> HashSet a

toList :: HashSet a -> [Item (HashSet a)]

Eq a => Eq (HashSet a)

Methods

(==) :: HashSet a -> HashSet a -> Bool

(/=) :: HashSet a -> HashSet a -> Bool

(Data a, Eq a, Hashable a) => Data (HashSet a)

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> HashSet a -> c (HashSet a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (HashSet a)

toConstr :: HashSet a -> Constr

dataTypeOf :: HashSet a -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c (HashSet a))

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (HashSet a))

gmapT :: (forall b. Data b => b -> b) -> HashSet a -> HashSet a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> HashSet a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> HashSet a -> r

gmapQ :: (forall d. Data d => d -> u) -> HashSet a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> HashSet a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> HashSet a -> m (HashSet a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> HashSet a -> m (HashSet a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> HashSet a -> m (HashSet a)

Ord a => Ord (HashSet a)

Methods

compare :: HashSet a -> HashSet a -> Ordering

(<) :: HashSet a -> HashSet a -> Bool

(<=) :: HashSet a -> HashSet a -> Bool

(>) :: HashSet a -> HashSet a -> Bool

(>=) :: HashSet a -> HashSet a -> Bool

max :: HashSet a -> HashSet a -> HashSet a

min :: HashSet a -> HashSet a -> HashSet a

(Eq a, Hashable a, Read a) => Read (HashSet a)

Methods

readsPrec :: Int -> ReadS (HashSet a)

readList :: ReadS [HashSet a]

readPrec :: ReadPrec (HashSet a)

readListPrec :: ReadPrec [HashSet a]

Show a => Show (HashSet a)

Methods

showsPrec :: Int -> HashSet a -> ShowS

show :: HashSet a -> String

showList :: [HashSet a] -> ShowS

(Hashable a, Eq a) => Semigroup (HashSet a)

Methods

(<>) :: HashSet a -> HashSet a -> HashSet a

sconcat :: NonEmpty (HashSet a) -> HashSet a

stimes :: Integral b => b -> HashSet a -> HashSet a

(Hashable a, Eq a) => Monoid (HashSet a)

Methods

mempty :: HashSet a

mappend :: HashSet a -> HashSet a -> HashSet a

mconcat :: [HashSet a] -> HashSet a

NFData a => NFData (HashSet a)

Methods

rnf :: HashSet a -> ()

Hashable a => Hashable (HashSet a)

Methods

hashWithSalt :: Int -> HashSet a -> Int

hash :: HashSet a -> Int

type Item (HashSet a)

type Item (HashSet a) = a

Construction

empty :: HashSet a

O(1) Construct an empty set.

singleton :: Hashable a => a -> HashSet a

O(1) Construct a set with a single element.

Combine

union :: (Eq a, Hashable a) => HashSet a -> HashSet a -> HashSet a

O(n+m) Construct a set containing all elements from both sets.

To obtain good performance, the smaller set must be presented as the first argument.

unions :: (Eq a, Hashable a) => [HashSet a] -> HashSet a

Construct a set containing all elements from a list of sets.

Basic interface

null :: HashSet a -> Bool

O(1) Return True if this set is empty, False otherwise.

size :: HashSet a -> Int

O(n) Return the number of elements in this set.

member :: (Eq a, Hashable a) => a -> HashSet a -> Bool

O(log n) Return True if the given value is present in this set, False otherwise.

insert :: (Eq a, Hashable a) => a -> HashSet a -> HashSet a

O(log n) Add the specified value to this set.

delete :: (Eq a, Hashable a) => a -> HashSet a -> HashSet a

O(log n) Remove the specified value from this set if present.

Transformations

map :: (Hashable b, Eq b) => (a -> b) -> HashSet a -> HashSet b

O(n) Transform this set by applying a function to every value. The resulting set may be smaller than the source.

Difference and intersection

difference :: (Eq a, Hashable a) => HashSet a -> HashSet a -> HashSet a

O(n) Difference of two sets. Return elements of the first set not existing in the second.

intersection :: (Eq a, Hashable a) => HashSet a -> HashSet a -> HashSet a

O(n) Intersection of two sets. Return elements present in both the first set and the second.

Folds

foldl' :: (a -> b -> a) -> a -> HashSet b -> a

O(n) Reduce this set by applying a binary operator to all elements, using the given starting value (typically the left-identity of the operator). Each application of the operator is evaluated before before using the result in the next application. This function is strict in the starting value.

foldr :: (b -> a -> a) -> a -> HashSet b -> a

O(n) Reduce this set by applying a binary operator to all elements, using the given starting value (typically the right-identity of the operator).

Filter

filter :: (a -> Bool) -> HashSet a -> HashSet a

O(n) Filter this set by retaining only elements satisfying a predicate.

Conversions

Lists

toList :: HashSet a -> [a]

O(n) Return a list of this set's elements. The list is produced lazily.

fromList :: (Eq a, Hashable a) => [a] -> HashSet a

O(n*min(W, n)) Construct a set from a list of elements.

HashMaps

toMap :: HashSet a -> HashMap a ()

O(1) Convert to the equivalent HashMap.

fromMap :: HashMap a () -> HashSet a

O(1) Convert from the equivalent HashMap.