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GHC 10.0.0.20260917 · lts/ghc-10.0.x · 77a8662 · 2026-10-31

Modulehashmap-1.3.3Haskell98

Data.HashSet

Persistent Set based on hashing, which is defined as

  data Set e = Data.IntMap.IntMap (Some e)

is an Data.IntMap.IntMap indexed by hash values of elements, containing a value of Some e. That contains either one e or a Set e with elements of the same hash values.

The interface of a Set is a suitable subset of IntSet and can be used as a drop-in replacement of Set.

The complexity of operations is determined by the complexities of Data.IntMap.IntMap and Set operations. See the sources of Set to see which operations from containers package are used.

Contents

Operators
Query
Construction
Combine
Filter
Map
Fold
Conversion

Synopsis

newtype Set
type HashSet
value \\
value null
value size
value member
value notMember
value isSubsetOf
value isProperSubsetOf
value empty
value singleton
value insert
value delete
value union
value unions
value difference
value intersection
value filter
value partition
value map
value fold
value elems
value toList
value fromList

Packagehashmap-1.3.3
Exports24
LanguageHaskell98
LicenceBSD-3-Clause
SourceHashSet.hs

newtypenewtype Set a

The abstract type of a Set. Its interface is a suitable subset of IntSet.

Instances8Eq, Data, Ord, Read, Show, Semigroup, …

Eq a => Eq (Set a)Defined in hashmap-1.3.3 · Data.HashSet
(Hashable a, Ord a, Data a) => Data (Set a)Defined in hashmap-1.3.3 · Data.HashSet
Ord a => Ord (Set a)Defined in hashmap-1.3.3 · Data.HashSet
(Hashable a, Ord a, Read a) => Read (Set a)Defined in hashmap-1.3.3 · Data.HashSet
Show a => Show (Set a)Defined in hashmap-1.3.3 · Data.HashSet
Ord a => Semigroup (Set a)Defined in hashmap-1.3.3 · Data.HashSet
Ord a => Monoid (Set a)Defined in hashmap-1.3.3 · Data.HashSet
NFData a => NFData (Set a)Defined in hashmap-1.3.3 · Data.HashSet

typetype HashSet a = Set a

Deprecated. HashSet is deprecated. Please use Set instead.

The HashSet is a type synonym for Set for backward compatibility. It is deprecated and will be removed in furture releases.

Operators

value(\\) :: Ord a => Set a -> Set a -> Set a

Same as difference.

Query

valuenull :: Set a -> Bool

Is the set empty?

valuesize :: Set a -> Int

Number of elements in the set.

valuemember :: (Hashable a, Ord a) => a -> Set a -> Bool

Is the element a member of the set?

valuenotMember :: (Hashable a, Ord a) => a -> Set a -> Bool

Is the element not a member of the set?

valueisSubsetOf :: Ord a => Set a -> Set a -> Bool

Is this a subset?

valueisProperSubsetOf :: Ord a => Set a -> Set a -> Bool

Is this a proper subset? (ie. a subset but not equal).

Construction

valueempty :: Set a

The empty set.

valuesingleton :: Hashable a => a -> Set a

A set of one element.

valueinsert :: (Hashable a, Ord a) => a -> Set a -> Set a

Add a value to the set. When the value is already an element of the set, it is replaced by the new one, ie. insert is left-biased.

valuedelete :: (Hashable a, Ord a) => a -> Set a -> Set a

Delete a value in the set. Returns the original set when the value was not present.

Combine

valueunion :: Ord a => Set a -> Set a -> Set a

The union of two sets.

valueunions :: Ord a => [Set a] -> Set a

The union of a list of sets.

valuedifference :: Ord a => Set a -> Set a -> Set a

Difference between two sets.

valueintersection :: Ord a => Set a -> Set a -> Set a

The intersection of two sets.

Filter

valuefilter :: Ord a => (a -> Bool) -> Set a -> Set a

Filter all elements that satisfy some predicate.

valuepartition :: Ord a => (a -> Bool) -> Set a -> (Set a, Set a)

Partition the set according to some predicate. The first set contains all elements that satisfy the predicate, the second all elements that fail the predicate.

Map

valuemap :: (Hashable b, Ord b) => (a -> b) -> Set a -> Set b

map f s is the set obtained by applying f to each element of s.

It's worth noting that the size of the result may be smaller if, for some (x,y), x /= y && f x == f y

Fold

valuefold :: (a -> b -> b) -> b -> Set a -> b

Fold over the elements of a set in an unspecified order.

Conversion

valueelems :: Set a -> [a]

The elements of a set. (For sets, this is equivalent to toList).

valuetoList :: Set a -> [a]

Convert the set to a list of elements.

valuefromList :: (Hashable a, Ord a) => [a] -> Set a

Create a set from a list of elements.