Data.HashSet.Internal

unordered-containers-0.2.20: Efficient hashing-based container types

Copyright | 2011 Bryan O'Sullivan
License | BSD-style
Maintainer | johan.tibell@gmail.com
Portability | portable
Safe Haskell | Trustworthy
Language | Haskell2010

Data.HashSet.Internal

Contents

- Construction
- Basic interface
- Transformations
- Combine
- Difference and intersection
- Folds
- Filter
- Conversions
  - Lists
- HashMaps

Description

# WARNING

This module is considered internal.

The Package Versioning Policy does not apply.

The contents of this module may change in any way whatsoever and without any warning between minor versions of this package.

Authors importing this module are expected to track development closely.

# Description

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 tries. 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. 32) so in practice these operations are constant time.

Synopsis

- newtype HashSet a = HashSet {
  - asMap :: HashMap a ()
  }
- empty :: HashSet a
- singleton :: Hashable a => a -> HashSet a
- null :: HashSet a -> Bool
- size :: HashSet a -> Int
- member :: (Eq a, Hashable a) => a -> HashSet a -> Bool
- insert :: (Eq a, Hashable a) => a -> HashSet a -> HashSet a
- delete :: (Eq a, Hashable a) => a -> HashSet a -> HashSet a
- isSubsetOf :: (Eq a, Hashable a) => HashSet a -> HashSet a -> Bool
- map :: (Hashable b, Eq b) => (a -> b) -> HashSet a -> HashSet b
- union :: Eq a => HashSet a -> HashSet a -> HashSet a
- unions :: Eq a => [HashSet a] -> HashSet a
- difference :: (Eq a, Hashable a) => HashSet a -> HashSet a -> HashSet a
- intersection :: Eq a => HashSet a -> HashSet a -> HashSet a
- foldr :: (b -> a -> a) -> a -> HashSet b -> a
- foldr' :: (b -> a -> a) -> a -> HashSet b -> a
- foldl :: (a -> b -> a) -> a -> HashSet b -> a
- foldl' :: (a -> b -> a) -> a -> HashSet b -> a
- filter :: (a -> Bool) -> HashSet a -> HashSet a
- toList :: HashSet a -> [a]
- fromList :: (Eq a, Hashable a) => [a] -> HashSet a
- toMap :: HashSet a -> HashMap a ()
- fromMap :: HashMap a () -> HashSet a
- keysSet :: HashMap k a -> HashSet k

# Documentation

newtype HashSet a #

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

Constructors

HashSet |
Fields asMap :: HashMap a ()

#### Instances

Instances details

Foldable HashSet # |
Instance details Defined in Data.HashSet.Internal Methods fold :: Monoid m => HashSet m -> m # foldMap :: Monoid m => (a -> m) -> HashSet a -> 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 # |
Instance details Defined in Data.HashSet.Internal Methods liftEq :: (a -> b -> Bool) -> HashSet a -> HashSet b -> Bool #
Ord1 HashSet # |
Instance details Defined in Data.HashSet.Internal Methods liftCompare :: (a -> b -> Ordering) -> HashSet a -> HashSet b -> Ordering #
Show1 HashSet # |
Instance details Defined in Data.HashSet.Internal Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> HashSet a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [HashSet a] -> ShowS #
NFData1 HashSet # | Since: 0.2.14.0
Instance details Defined in Data.HashSet.Internal Methods liftRnf :: (a -> ()) -> HashSet a -> () #
Hashable1 HashSet # |
Instance details Defined in Data.HashSet.Internal Methods liftHashWithSalt :: (Int -> a -> Int) -> Int -> HashSet a -> Int #
Lift a => Lift (HashSet a :: Type) # | Since: 0.2.17.0
Instance details Defined in Data.HashSet.Internal Methods lift :: Quote m => HashSet a -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => HashSet a -> Code m (HashSet a) #
(Data a, Eq a, Hashable a) => Data (HashSet a) # |
Instance details Defined in Data.HashSet.Internal 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 :: forall r r'. (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) #
(Hashable a, Eq a) => Monoid (HashSet a) # | `mempty` = `empty` `mappend` = `union` \(O(n+m)\) To obtain good performance, the smaller set must be presented as the first argument. #### Examples Expand
    >>> mappend (fromList [1,2]) (fromList [2,3])
    fromList [1,2,3]
Instance details Defined in Data.HashSet.Internal Methods mempty :: HashSet a # mappend :: HashSet a -> HashSet a -> HashSet a # mconcat :: [HashSet a] -> HashSet a #
(Hashable a, Eq a) => Semigroup (HashSet a) # | `<>` = `union` \(O(n+m)\) To obtain good performance, the smaller set must be presented as the first argument. #### Examples Expand
    >>> fromList [1,2] <> fromList [2,3]
    fromList [1,2,3]
Instance details Defined in Data.HashSet.Internal Methods (<>) :: HashSet a -> HashSet a -> HashSet a # sconcat :: NonEmpty (HashSet a) -> HashSet a # stimes :: Integral b => b -> HashSet a -> HashSet a #
(Eq a, Hashable a) => IsList (HashSet a) # |
Instance details Defined in Data.HashSet.Internal Associated Types
type Item (HashSet a) |
Instance details Defined in Data.HashSet.Internal type Item (HashSet a) = a
Methods fromList :: [Item (HashSet a)] -> HashSet a # fromListN :: Int -> [Item (HashSet a)] -> HashSet a # toList :: HashSet a -> [Item (HashSet a)] #
(Eq a, Hashable a, Read a) => Read (HashSet a) # |
Instance details Defined in Data.HashSet.Internal Methods readsPrec :: Int -> ReadS (HashSet a) # readList :: ReadS [HashSet a] # readPrec :: ReadPrec (HashSet a) # readListPrec :: ReadPrec [HashSet a] #
Show a => Show (HashSet a) # |
Instance details Defined in Data.HashSet.Internal Methods showsPrec :: Int -> HashSet a -> ShowS # show :: HashSet a -> String # showList :: [HashSet a] -> ShowS #
NFData a => NFData (HashSet a) # |
Instance details Defined in Data.HashSet.Internal Methods rnf :: HashSet a -> () #
Eq a => Eq (HashSet a) # | Note that, in the presence of hash collisions, equal `HashSet`s may behave differently, i.e. extensionality may be violated:
    >>> data D = A | B deriving (Eq, Show)
    >>> instance Hashable D where hashWithSalt salt _d = salt
    >>> x = fromList [A, B]
    >>> y = fromList [B, A]
    >>> x == y
    True
    >>> toList x
    [A,B]
    >>> toList y
    [B,A]
In general, the lack of extensionality can be observed with any function that depends on the key ordering, such as folds and traversals.
Instance details Defined in Data.HashSet.Internal Methods (==) :: HashSet a -> HashSet a -> Bool # (/=) :: HashSet a -> HashSet a -> Bool #
Ord a => Ord (HashSet a) # |
Instance details Defined in Data.HashSet.Internal 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 #
Hashable a => Hashable (HashSet a) # |
Instance details Defined in Data.HashSet.Internal Methods hashWithSalt :: Int -> HashSet a -> Int # hash :: HashSet a -> Int #
type Item (HashSet a) # |
Instance details Defined in Data.HashSet.Internal type Item (HashSet a) = a

# Construction

empty :: HashSet a #

\(O(1)\) Construct an empty set.

    >>> HashSet.empty
    fromList []

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

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

    >>> HashSet.singleton 1
    fromList [1]

# Basic interface

null :: HashSet a -> Bool #

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

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

size :: HashSet a -> Int #

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

    >>> HashSet.size HashSet.empty
    0
    >>> HashSet.size (HashSet.fromList [1,2,3])
    3

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.

    >>> HashSet.member 1 (Hashset.fromList [1,2,3])
    True
    >>> HashSet.member 1 (Hashset.fromList [4,5,6])
    False

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

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

    >>> HashSet.insert 1 HashSet.empty
    fromList [1]

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

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

    >>> HashSet.delete 1 (HashSet.fromList [1,2,3])
    fromList [2,3]
    >>> HashSet.delete 1 (HashSet.fromList [4,5,6])
    fromList [4,5,6]

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

\(O(n \log m)\) Inclusion of sets.

#### Examples

Expand

    >>> fromList [1,3] `isSubsetOf` fromList [1,2,3]
    True

    >>> fromList [1,2] `isSubsetOf` fromList [1,3]
    False

Since: 0.2.12

# 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.

    >>> HashSet.map show (HashSet.fromList [1,2,3])
    HashSet.fromList ["1","2","3"]

# Combine

union :: Eq 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.

    >>> union (fromList [1,2]) (fromList [2,3])
    fromList [1,2,3]

unions :: Eq a => [HashSet a] -> HashSet a #

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

# 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.

    >>> HashSet.difference (HashSet.fromList [1,2,3]) (HashSet.fromList [2,3,4])
    fromList [1]

intersection :: Eq a => HashSet a -> HashSet a -> HashSet a #

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

    >>> HashSet.intersection (HashSet.fromList [1,2,3]) (HashSet.fromList [2,3,4])
    fromList [2,3]

# Folds

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).

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). Each application of the operator is evaluated before before using the result in the next application. This function is strict in the starting value.

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).

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.

# 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 set to the equivalent `HashMap` with `()` values.

    >>> HashSet.toMap (HashSet.singleton 1)
    fromList [(1,())]

fromMap :: HashMap a () -> HashSet a #

\(O(1)\) Convert from the equivalent `HashMap` with `()` values.

    >>> HashSet.fromMap (HashMap.singleton 1 ())
    fromList [1]

keysSet :: HashMap k a -> HashSet k #

\(O(n)\) Produce a `HashSet` of all the keys in the given `HashMap`.

    >>> HashSet.keysSet (HashMap.fromList [(1, "a"), (2, "b")]
    fromList [1,2]

Since: 0.2.10.0