scala.collection.immutable

# HashSet

#### class HashSet[A] extends AbstractSet[A] with Set[A] with GenericSetTemplate[A, HashSet] with SetLike[A, HashSet[A]] with CustomParallelizable[A, ParHashSet[A]] with Serializable

This class implements immutable sets using a hash trie.

Note: the builder of a hash set returns specialized representations `EmptySet`,`Set1`,..., `Set4` for sets of `size <= 4`.

A

  the type of the elements contained in this hash set.

Annotations
  @SerialVersionUID( uid = 2L )
Source
  HashSet.scala
Version

  2.8

Since

  2.3

Linear Supertypes
Serializable, Serializable, CustomParallelizable[A, ParHashSet[A]], Set[A], Iterable[A], Traversable[A], Immutable, AbstractSet[A], Set[A], SetLike[A, HashSet[A]], Subtractable[A, HashSet[A]], GenSet[A], GenericSetTemplate[A, HashSet], GenSetLike[A, HashSet[A]], (A) ⇒ Boolean, AbstractIterable[A], Iterable[A], IterableLike[A, HashSet[A]], Equals, GenIterable[A], GenIterableLike[A, HashSet[A]], AbstractTraversable[A], Traversable[A], GenTraversable[A], GenericTraversableTemplate[A, HashSet], TraversableLike[A, HashSet[A]], GenTraversableLike[A, HashSet[A]], Parallelizable[A, ParHashSet[A]], TraversableOnce[A], GenTraversableOnce[A], FilterMonadic[A, HashSet[A]], HasNewBuilder[A, HashSet[A]], AnyRef, Any
Known Subclasses
HashSet1, HashTrieSet
Ordering

1. Alphabetic
2. By inheritance

Inherited

1. Hide All
2. Show all

1. HashSet
2. Serializable
3. Serializable
4. CustomParallelizable
5. Set
6. Iterable
7. Traversable
8. Immutable
9. AbstractSet
10. Set
11. SetLike
12. Subtractable
13. GenSet
14. GenericSetTemplate
15. GenSetLike
16. Function1
17. AbstractIterable
18. Iterable
19. IterableLike
20. Equals
21. GenIterable
22. GenIterableLike
23. AbstractTraversable
24. Traversable
25. GenTraversable
26. GenericTraversableTemplate
27. TraversableLike
28. GenTraversableLike
29. Parallelizable
30. TraversableOnce
31. GenTraversableOnce
32. FilterMonadic
33. HasNewBuilder
34. AnyRef
35. Any

Visibility

1. Public
2. All

### Instance Constructors

1. #### new HashSet()

### Type Members

1. #### type Self = HashSet[A]

   The type implementing this traversable

   The type implementing this traversable

   Attributes
     protected
   Definition Classes
     TraversableLike

2. #### class WithFilter extends FilterMonadic[A, Repr]

   A class supporting filtered operations.

### Value Members

1. #### final def !=(arg0: AnyRef): Boolean

   Definition Classes
     AnyRef

2. #### final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     Any

3. #### final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any

4. #### def &(that: GenSet[A]): HashSet[A]

   Computes the intersection between this set and another set.

   Computes the intersection between this set and another set.

   Note: Same as `intersect`.

   that

     the set to intersect with.

   returns

     a new set consisting of all elements that are both in this set and in the given set `that`.

   Definition Classes
     GenSetLike

5. #### def &~(that: GenSet[A]): HashSet[A]

   The difference of this set and another set.

   The difference of this set and another set.

   Note: Same as `diff`.

   that

     the set of elements to exclude.

   returns

     a set containing those elements of this set that are not also contained in the given set `that`.

   Definition Classes
     GenSetLike

6. #### def +(elem1: A, elem2: A, elems: A*): HashSet[A]

   Creates a new immutable hash set with additional elements.

   Creates a new immutable hash set with additional elements.

   This method takes two or more elements to be added. Another overloaded variant of this method handles the case where a single element is added.

   elem1

     the first element to add.

   elem2

     the second element to add.

   elems

     the remaining elements to add.

   returns

     a new immutable hash set with the given elements added.

   Definition Classes
     HashSet → SetLike

7. #### def +(e: A): HashSet[A]

   Creates a new set with an additional element, unless the element is already present.

   Creates a new set with an additional element, unless the element is already present.

   returns

     a new set that contains all elements of this set and that also contains `elem`.

   Definition Classes
     HashSet → SetLike → GenSetLike

8. #### def ++(elems: GenTraversableOnce[A]): HashSet[A]

   Creates a new immutable hash set by adding all elements contained in another collection to this immutable hash set.

   Creates a new immutable hash set by adding all elements contained in another collection to this immutable hash set.

   elems

     the collection containing the added elements.

   returns

     a new immutable hash set with the given elements added.

   Definition Classes
     SetLike

9. #### def ++[B](that: GenTraversableOnce[B]): immutable.HashSet[B]

   [use case]

   [use case]
   B

     the element type of the returned collection.

   that

     the traversable to append.

   returns

     a new immutable hash set which contains all elements of this immutable hash set followed by all elements of `that`.

   Definition Classes
     TraversableLike → GenTraversableLike

10. #### def ++:[B >: A, That](that: Traversable[B])(implicit bf: CanBuildFrom[HashSet[A], B, That]): That

    As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    It differs from `++` in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.

    Example:

            scala> val x = List(1)
            x: List[Int] = List(1)

            scala> val y = LinkedList(2)
            y: scala.collection.mutable.LinkedList[Int] = LinkedList(2)

            scala> val z = x ++: y
            z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

    This overload exists because: for the implementation of `++:` we should reuse that of `++` because many collections override it with more efficient versions.

    Since `TraversableOnce` has no `++` method, we have to implement that directly, but `Traversable` and down can use the overload.

    B

      the element type of the returned collection.

    That

      the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

    that

      the traversable to append.

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      a new collection of type `That` which contains all elements of this immutable hash set followed by all elements of `that`.

    Definition Classes
      TraversableLike

11. #### def ++:[B](that: TraversableOnce[B]): immutable.HashSet[B]

    [use case]

    [use case]
    B

      the element type of the returned collection.

    that

      the traversable to append.

    returns

      a new immutable hash set which contains all elements of this immutable hash set followed by all elements of `that`.

    Definition Classes
      TraversableLike

12. #### def -(e: A): HashSet[A]

    Creates a new set with a given element removed from this set.

    Creates a new set with a given element removed from this set.

    returns

      a new set that contains all elements of this set but that does not contain `elem`.

    Definition Classes
      HashSet → SetLike → Subtractable → GenSetLike

13. #### def -(elem1: A, elem2: A, elems: A*): HashSet[A]

    Creates a new immutable hash set from this immutable hash set with some elements removed.

    Creates a new immutable hash set from this immutable hash set with some elements removed.

    This method takes two or more elements to be removed. Another overloaded variant of this method handles the case where a single element is removed.

    elem1

      the first element to remove.

    elem2

      the second element to remove.

    elems

      the remaining elements to remove.

    returns

      a new immutable hash set that contains all elements of the current immutable hash set except one less occurrence of each of the given elements.

    Definition Classes
      Subtractable

14. #### def --(xs: GenTraversableOnce[A]): HashSet[A]

    Creates a new immutable hash set from this immutable hash set by removing all elements of another collection.

    Creates a new immutable hash set from this immutable hash set by removing all elements of another collection.

    returns

      a new immutable hash set that contains all elements of the current immutable hash set except one less occurrence of each of the elements of `elems`.

    Definition Classes
      Subtractable

15. #### def /:[B](z: B)(op: (B, A) ⇒ B): B

    Applies a binary operator to a start value and all elements of this immutable hash set, going left to right.

    Applies a binary operator to a start value and all elements of this immutable hash set, going left to right.

    Note: `/:` is alternate syntax for `foldLeft`; `z /: xs` is the same as `xs foldLeft z`.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = (5 /: a)(_+_)
             b: Int = 15

             scala> val c = (5 /: a)((x,y) => x + y)
             c: Int = 15

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this immutable hash set, going left to right with the start value `z` on the left:

                      op(...op(op(z, x1), x2), ..., xn)

      where `x1, ..., xn` are the elements of this immutable hash set.

    Definition Classes
      TraversableOnce → GenTraversableOnce

16. #### def /:\[A1 >: A](z: A1)(op: (A1, A1) ⇒ A1): A1

    A syntactic sugar for out of order folding.

    A syntactic sugar for out of order folding. See `fold`.

    Example:

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = (a /:\ 5)(_+_)
             b: Int = 15

    Definition Classes
      GenTraversableOnce

17. #### def :\[B](z: B)(op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this immutable hash set and a start value, going right to left.

    Applies a binary operator to all elements of this immutable hash set and a start value, going right to left.

    Note: `:\` is alternate syntax for `foldRight`; `xs :\ z` is the same as `xs foldRight z`.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = (a :\ 5)(_+_)
             b: Int = 15

             scala> val c = (a :\ 5)((x,y) => x + y)
             c: Int = 15

    B

      the result type of the binary operator.

    z

      the start value

    op

      the binary operator

    returns

      the result of inserting `op` between consecutive elements of this immutable hash set, going right to left with the start value `z` on the right:

                      op(x1, op(x2, ... op(xn, z)...))

      where `x1, ..., xn` are the elements of this immutable hash set.

    Definition Classes
      TraversableOnce → GenTraversableOnce

18. #### final def ==(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

19. #### final def ==(arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality. The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

    returns

      `true` if the receiver object is equivalent to the argument; `false` otherwise.

    Definition Classes
      Any

20. #### def addString(b: StringBuilder): StringBuilder

    Appends all elements of this immutable hash set to a string builder.

    Appends all elements of this immutable hash set to a string builder. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set without any separator string.

    Example:

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = new StringBuilder()
             b: StringBuilder =

             scala> val h = a.addString(b)
             b: StringBuilder = 1234

    b

      the string builder to which elements are appended.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableOnce

21. #### def addString(b: StringBuilder, sep: String): StringBuilder

    Appends all elements of this immutable hash set to a string builder using a separator string.

    Appends all elements of this immutable hash set to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set, separated by the string `sep`.

    Example:

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = new StringBuilder()
             b: StringBuilder =

             scala> a.addString(b, ", ")
             res0: StringBuilder = 1, 2, 3, 4

    b

      the string builder to which elements are appended.

    sep

      the separator string.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableOnce

22. #### def addString(b: StringBuilder, start: String, sep: String, end: String): StringBuilder

    Appends all elements of this immutable hash set to a string builder using start, end, and separator strings.

    Appends all elements of this immutable hash set to a string builder using start, end, and separator strings. The written text begins with the string `start` and ends with the string `end`. Inside, the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set are separated by the string `sep`.

    Example:

             scala> val a = LinkedList(1,2,3,4)
             a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)

             scala> val b = new StringBuilder()
             b: StringBuilder =

             scala> a.addString(b, "LinkedList(", ", ", ")")
             res1: StringBuilder = LinkedList(1, 2, 3, 4)

    b

      the string builder to which elements are appended.

    start

      the starting string.

    sep

      the separator string.

    end

      the ending string.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableOnce

23. #### def aggregate[B](z: B)(seqop: (B, A) ⇒ B, combop: (B, B) ⇒ B): B

    Aggregates the results of applying an operator to subsequent elements.

    Aggregates the results of applying an operator to subsequent elements.

    This is a more general form of `fold` and `reduce`. It has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using `seqop` to update the result, and then applies `combop` to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so `combop` may be invoked an arbitrary number of times.

    For example, one might want to process some elements and then produce a `Set`. In this case, `seqop` would process an element and append it to the list, while `combop` would concatenate two lists from different partitions together. The initial value `z` would be an empty set.

           pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)

    Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).

    B

      the type of accumulated results

    z

      the initial value for the accumulated result of the partition - this will typically be the neutral element for the `seqop` operator (e.g. `Nil` for list concatenation or `0` for summation)

    seqop

      an operator used to accumulate results within a partition

    combop

      an associative operator used to combine results from different partitions

    Definition Classes
      TraversableOnce → GenTraversableOnce

24. #### def andThen[A](g: (Boolean) ⇒ A): (A) ⇒ A

    Composes two instances of Function1 in a new Function1, with this function applied first.

    Composes two instances of Function1 in a new Function1, with this function applied first.

    A

      the result type of function `g`

    g

      a function R => A

    returns

      a new function `f` such that `f(x) == g(apply(x))`

    Definition Classes
      Function1

25. #### def apply(elem: A): Boolean

    Tests if some element is contained in this set.

    Tests if some element is contained in this set.

    This method is equivalent to `contains`. It allows sets to be interpreted as predicates.

    elem

      the element to test for membership.

    returns

      `true` if `elem` is contained in this set, `false` otherwise.

    Definition Classes
      GenSetLike → Function1

26. #### final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type `T0`.

    Cast the receiver object to be of type `T0`.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

      the receiver object.

    Definition Classes
      Any
    Exceptions thrown
      ClassCastException

      if the receiver object is not an instance of the erasure of type `T0`.

27. #### def canEqual(that: Any): Boolean

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    that

      The object with which this immutable hash set should be compared

    returns

      `true`, if this immutable hash set can possibly equal `that`, `false` otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.

    Definition Classes
      IterableLike → Equals

28. #### def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the `clone` method is platform dependent.

    returns

      a copy of the receiver object.

    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws()
    Note

      not specified by SLS as a member of AnyRef

29. #### def collect[B](pf: PartialFunction[A, B]): immutable.HashSet[B]

    [use case]

    [use case]
    B

      the element type of the returned collection.

    pf

      the partial function which filters and maps the immutable hash set.

    returns

      a new immutable hash set resulting from applying the given partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

30. #### def collectFirst[B](pf: PartialFunction[A, B]): Option[B]

    Finds the first element of the immutable hash set for which the given partial function is defined, and applies the partial function to it.

    Finds the first element of the immutable hash set for which the given partial function is defined, and applies the partial function to it.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    pf

      the partial function

    returns

      an option value containing pf applied to the first value for which it is defined, or `None` if none exists.

    Definition Classes
      TraversableOnce
    Example:

    1. `Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)`

31. #### def companion: GenericCompanion[HashSet]

    The factory companion object that builds instances of class immutable.

    The factory companion object that builds instances of class immutable.HashSet. (or its `Iterable` superclass where class immutable.HashSet is not a `Seq`.)

    Definition Classes
      HashSet → Set → Iterable → Traversable → Set → GenSet → Iterable → GenIterable → Traversable → GenTraversable → GenericTraversableTemplate

32. #### def compose[A](g: (A) ⇒ A): (A) ⇒ Boolean

    Composes two instances of Function1 in a new Function1, with this function applied last.

    Composes two instances of Function1 in a new Function1, with this function applied last.

    A

      the type to which function `g` can be applied

    g

      a function A => T1

    returns

      a new function `f` such that `f(x) == apply(g(x))`

    Definition Classes
      Function1

33. #### def contains(e: A): Boolean

    Tests if some element is contained in this set.

    Tests if some element is contained in this set.

    returns

      `true` if `elem` is contained in this set, `false` otherwise.

    Definition Classes
      HashSet → SetLike → GenSetLike

34. #### def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case]

    [use case]
    xs

      the array to fill.

    start

      the starting index.

    len

      the maximal number of elements to copy.

    Definition Classes
      IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce

35. #### def copyToArray(xs: Array[A]): Unit

    [use case]

    [use case]
    xs

      the array to fill.

    Definition Classes
      TraversableOnce → GenTraversableOnce

36. #### def copyToArray(xs: Array[A], start: Int): Unit

    [use case]

    [use case]
    xs

      the array to fill.

    start

      the starting index.

    Definition Classes
      TraversableOnce → GenTraversableOnce

37. #### def copyToBuffer[B >: A](dest: Buffer[B]): Unit

    Copies all elements of this immutable hash set to a buffer.

    Copies all elements of this immutable hash set to a buffer.

    dest

      The buffer to which elements are copied.

    Definition Classes
      TraversableOnce

38. #### def count(p: (A) ⇒ Boolean): Int

    Counts the number of elements in the immutable hash set which satisfy a predicate.

    Counts the number of elements in the immutable hash set which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      the number of elements satisfying the predicate `p`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

39. #### def diff(that: GenSet[A]): HashSet[A]

    Computes the difference of this set and another set.

    Computes the difference of this set and another set.

    that

      the set of elements to exclude.

    returns

      a set containing those elements of this set that are not also contained in the given set `that`.

    Definition Classes
      SetLike → GenSetLike

40. #### def drop(n: Int): HashSet[A]

    Selects all elements except first n ones.

    Selects all elements except first n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

      the number of elements to drop from this immutable hash set.

    returns

      a immutable hash set consisting of all elements of this immutable hash set except the first `n` ones, or else the empty immutable hash set, if this immutable hash set has less than `n` elements.

    Definition Classes
      IterableLike → TraversableLike → GenTraversableLike

41. #### def dropRight(n: Int): HashSet[A]

    Selects all elements except last n ones.

    Selects all elements except last n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

      The number of elements to take

    returns

      a immutable hash set consisting of all elements of this immutable hash set except the last `n` ones, or else the empty immutable hash set, if this immutable hash set has less than `n` elements.

    Definition Classes
      IterableLike

42. #### def dropWhile(p: (A) ⇒ Boolean): HashSet[A]

    Drops longest prefix of elements that satisfy a predicate.

    Drops longest prefix of elements that satisfy a predicate.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    p

      The predicate used to test elements.

    returns

      the longest suffix of this immutable hash set whose first element does not satisfy the predicate `p`.

    Definition Classes
      TraversableLike → GenTraversableLike

43. #### def elemHashCode(key: A): Int

    Attributes
      protected

44. #### def empty: HashSet[A]

    The empty set of the same type as this set

    The empty set of the same type as this set

    returns

      an empty set of type `This`.

    Definition Classes
      HashSet → SetLike → GenericSetTemplate

45. #### final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

    - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
    - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
    - `null.eq(null)` returns `true`.

    When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

    returns

      `true` if the argument is a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

46. #### def equals(that: Any): Boolean

    Compares this set with another object for equality.

    Compares this set with another object for equality.

    Note: This operation contains an unchecked cast: if `that` is a set, it will assume with an unchecked cast that it has the same element type as this set. Any subsequent ClassCastException is treated as a `false` result.

    that

      the other object

    returns

      `true` if `that` is a set which contains the same elements as this set.

    Definition Classes
      GenSetLike → Equals → AnyRef → Any

47. #### def exists(p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for some of the elements of this immutable hash set.

    Tests whether a predicate holds for some of the elements of this immutable hash set.

    p

      the predicate used to test elements.

    returns

      `true` if the given predicate `p` holds for some of the elements of this immutable hash set, otherwise `false`.

    Definition Classes
      IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce

48. #### def filter(p: (A) ⇒ Boolean): HashSet[A]

    Selects all elements of this immutable hash set which satisfy a predicate.

    Selects all elements of this immutable hash set which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new immutable hash set consisting of all elements of this immutable hash set that satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

49. #### def filterNot(p: (A) ⇒ Boolean): HashSet[A]

    Selects all elements of this immutable hash set which do not satisfy a predicate.

    Selects all elements of this immutable hash set which do not satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new immutable hash set consisting of all elements of this immutable hash set that do not satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

50. #### def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws()
    Note

      not specified by SLS as a member of AnyRef

51. #### def find(p: (A) ⇒ Boolean): Option[A]

    Finds the first element of the immutable hash set satisfying a predicate, if any.

    Finds the first element of the immutable hash set satisfying a predicate, if any.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    p

      the predicate used to test elements.

    returns

      an option value containing the first element in the immutable hash set that satisfies `p`, or `None` if none exists.

    Definition Classes
      IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce

52. #### def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): immutable.HashSet[B]

    [use case]

    [use case]
    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new immutable hash set resulting from applying the given collection-valued function `f` to each element of this immutable hash set and concatenating the results.

    Definition Classes
      TraversableLike → GenTraversableLike → FilterMonadic

53. #### def fold[A1 >: A](z: A1)(op: (A1, A1) ⇒ A1): A1

    Folds the elements of this immutable hash set using the specified associative binary operator.

    Folds the elements of this immutable hash set using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    A1

      a type parameter for the binary operator, a supertype of `A`.

    z

      a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., `Nil` for list concatenation, 0 for addition, or 1 for multiplication.)

    op

      a binary operator that must be associative

    returns

      the result of applying fold operator `op` between all the elements and `z`

    Definition Classes
      TraversableOnce → GenTraversableOnce

54. #### def foldLeft[B](z: B)(op: (B, A) ⇒ B): B

    Applies a binary operator to a start value and all elements of this immutable hash set, going left to right.

    Applies a binary operator to a start value and all elements of this immutable hash set, going left to right.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this immutable hash set, going left to right with the start value `z` on the left:

                      op(...op(z, x1), x2, ..., xn)

      where `x1, ..., xn` are the elements of this immutable hash set.

    Definition Classes
      TraversableOnce → GenTraversableOnce

55. #### def foldRight[B](z: B)(op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this immutable hash set and a start value, going right to left.

    Applies a binary operator to all elements of this immutable hash set and a start value, going right to left.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this immutable hash set, going right to left with the start value `z` on the right:

                      op(x1, op(x2, ... op(xn, z)...))

      where `x1, ..., xn` are the elements of this immutable hash set.

    Definition Classes
      IterableLike → TraversableOnce → GenTraversableOnce

56. #### def forall(p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all elements of this immutable hash set.

    Tests whether a predicate holds for all elements of this immutable hash set.

    p

      the predicate used to test elements.

    returns

      `true` if the given predicate `p` holds for all elements of this immutable hash set, otherwise `false`.

    Definition Classes
      IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce

57. #### def foreach(f: (A) ⇒ Unit): Unit

    [use case]

    [use case]
    f

      the function that is applied for its side-effect to every element. The result of function `f` is discarded.

    Definition Classes
      HashSet → IterableLike → GenericTraversableTemplate → TraversableLike → GenTraversableLike → TraversableOnce → GenTraversableOnce → FilterMonadic

58. #### def genericBuilder[B]: Builder[B, HashSet[B]]

    The generic builder that builds instances of immutable.

    The generic builder that builds instances of immutable.HashSet at arbitrary element types.

    Definition Classes
      GenericTraversableTemplate

59. #### def get0(key: A, hash: Int, level: Int): Boolean

    Attributes
      protected

60. #### final def getClass(): Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

      a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
      AnyRef → Any
    Note

      not specified by SLS as a member of AnyRef

61. #### def groupBy[K](f: (A) ⇒ K): Map[K, HashSet[A]]

    Partitions this immutable hash set into a map of immutable hash sets according to some discriminator function.

    Partitions this immutable hash set into a map of immutable hash sets according to some discriminator function.

    Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new immutable hash set.

    K

      the type of keys returned by the discriminator function.

    f

      the discriminator function.

    returns

      A map from keys to immutable hash sets such that the following invariant holds:

                          (xs partition f)(k) = xs filter (x => f(x) == k)

      That is, every key `k` is bound to a immutable hash set of those elements `x` for which `f(x)` equals `k`.

    Definition Classes
      TraversableLike → GenTraversableLike

62. #### def grouped(size: Int): Iterator[HashSet[A]]

    Partitions elements in fixed size immutable hash sets.

    Partitions elements in fixed size immutable hash sets.

    size

      the number of elements per group

    returns

      An iterator producing immutable hash sets of size `size`, except the last will be truncated if the elements don't divide evenly.

    Definition Classes
      IterableLike
    See also

      Iterator#grouped

63. #### def hasDefiniteSize: Boolean

    Tests whether this immutable hash set is known to have a finite size.

    Tests whether this immutable hash set is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as `Stream`, the predicate returns `true` if all elements have been computed. It returns `false` if the stream is not yet evaluated to the end.

    Note: many collection methods will not work on collections of infinite sizes.

    returns

      `true` if this collection is known to have finite size, `false` otherwise.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

64. #### def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in Any.

    returns

      the hash code value for this object.

    Definition Classes
      GenSetLike → AnyRef → Any

65. #### def head: A

    Selects the first element of this immutable hash set.

    Selects the first element of this immutable hash set.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the first element of this immutable hash set.

    Definition Classes
      IterableLike → GenIterableLike → TraversableLike → GenTraversableLike
    Exceptions thrown
      `NoSuchElementException`

      if the immutable hash set is empty.

66. #### def headOption: Option[A]

    Optionally selects the first element.

    Optionally selects the first element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the first element of this immutable hash set if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableLike

67. #### final def improve(hcode: Int): Int

    Attributes
      protected

68. #### def init: HashSet[A]

    Selects all elements except the last.

    Selects all elements except the last.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      a immutable hash set consisting of all elements of this immutable hash set except the last one.

    Definition Classes
      TraversableLike
    Exceptions thrown
      `UnsupportedOperationException`

      if the immutable hash set is empty.

69. #### def inits: Iterator[HashSet[A]]

    Iterates over the inits of this immutable hash set.

    Iterates over the inits of this immutable hash set. The first value will be this immutable hash set and the final one will be an empty immutable hash set, with the intervening values the results of successive applications of `init`.

    returns

      an iterator over all the inits of this immutable hash set

    Definition Classes
      TraversableLike
    Example:

    1. `List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)`

70. #### def intersect(that: GenSet[A]): HashSet[A]

    Computes the intersection between this set and another set.

    Computes the intersection between this set and another set.

    that

      the set to intersect with.

    returns

      a new set consisting of all elements that are both in this set and in the given set `that`.

    Definition Classes
      GenSetLike

71. #### def isEmpty: Boolean

    Tests if this set is empty.

    Tests if this set is empty.

    returns

      `true` if there is no element in the set, `false` otherwise.

    Definition Classes
      SetLike → IterableLike → GenIterableLike → TraversableLike → TraversableOnce → GenTraversableOnce

72. #### final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any

73. #### final def isTraversableAgain: Boolean

    Tests whether this immutable hash set can be repeatedly traversed.

    Tests whether this immutable hash set can be repeatedly traversed.

    returns

      `true`

    Definition Classes
      GenTraversableLike → GenTraversableOnce

74. #### def iterator: Iterator[A]

    Creates a new iterator over all elements contained in this iterable object.

    Creates a new iterator over all elements contained in this iterable object.

    returns

      the new iterator

    Definition Classes
      HashSet → GenSetLike → IterableLike → GenIterableLike

75. #### def last: A

    Selects the last element.

    Selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      The last element of this immutable hash set.

    Definition Classes
      TraversableLike
    Exceptions thrown
      NoSuchElementException

      If the immutable hash set is empty.

76. #### def lastOption: Option[A]

    Optionally selects the last element.

    Optionally selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the last element of this immutable hash set$ if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableLike

77. #### def map[B](f: (A) ⇒ B): immutable.HashSet[B]

    [use case]

    [use case]
    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new immutable hash set resulting from applying the given function `f` to each element of this immutable hash set and collecting the results.

    Definition Classes
      SetLike → TraversableLike → GenTraversableLike → FilterMonadic

78. #### def max: A

    [use case]

    [use case]
    returns

      the largest element of this immutable hash set.

    Definition Classes
      TraversableOnce → GenTraversableOnce

79. #### def maxBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Definition Classes
      TraversableOnce → GenTraversableOnce

80. #### def min: A

    [use case]

    [use case]
    returns

      the smallest element of this immutable hash set

    Definition Classes
      TraversableOnce → GenTraversableOnce

81. #### def minBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Definition Classes
      TraversableOnce → GenTraversableOnce

82. #### def mkString: String

    Displays all elements of this immutable hash set in a string.

    Displays all elements of this immutable hash set in a string.

    returns

      a string representation of this immutable hash set. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set follow each other without any separator string.

    Definition Classes
      TraversableOnce → GenTraversableOnce

83. #### def mkString(sep: String): String

    Displays all elements of this immutable hash set in a string using a separator string.

    Displays all elements of this immutable hash set in a string using a separator string.

    sep

      the separator string.

    returns

      a string representation of this immutable hash set. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set are separated by the string `sep`.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("|") = "1|2|3"`

84. #### def mkString(start: String, sep: String, end: String): String

    Displays all elements of this immutable hash set in a string using start, end, and separator strings.

    Displays all elements of this immutable hash set in a string using start, end, and separator strings.

    start

      the starting string.

    sep

      the separator string.

    end

      the ending string.

    returns

      a string representation of this immutable hash set. The resulting string begins with the string `start` and ends with the string `end`. Inside, the string representations (w.r.t. the method `toString`) of all elements of this immutable hash set are separated by the string `sep`.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"`

85. #### final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

86. #### def newBuilder: Builder[A, HashSet[A]]

    A common implementation of `newBuilder` for all sets in terms of `empty`.

    A common implementation of `newBuilder` for all sets in terms of `empty`. Overridden for mutable sets in `mutable.SetLike`.

    Attributes
      protected[this]
    Definition Classes
      SetLike → TraversableLike → HasNewBuilder

87. #### def nonEmpty: Boolean

    Tests whether the immutable hash set is not empty.

    Tests whether the immutable hash set is not empty.

    returns

      `true` if the immutable hash set contains at least one element, `false` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

88. #### final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

89. #### final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

90. #### def par: ParHashSet[A]

    Returns a parallel implementation of this collection.

    Returns a parallel implementation of this collection.

    For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, `par` takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.

    Specific collections (e.g. `ParArray` or `mutable.ParHashMap`) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, `par` takes constant or sublinear time.

    All parallel collections return a reference to themselves.

    returns

      a parallel implementation of this collection

    Definition Classes
      HashSet → CustomParallelizable → Parallelizable

91. #### def parCombiner: Combiner[A, ParHashSet[A]]

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    returns

      a combiner for the parallel collection of type `ParRepr`

    Attributes
      protected[this]
    Definition Classes
      CustomParallelizable → Parallelizable

92. #### def partition(p: (A) ⇒ Boolean): (HashSet[A], HashSet[A])

    Partitions this immutable hash set in two immutable hash sets according to a predicate.

    Partitions this immutable hash set in two immutable hash sets according to a predicate.

    p

      the predicate on which to partition.

    returns

      a pair of immutable hash sets: the first immutable hash set consists of all elements that satisfy the predicate `p` and the second immutable hash set consists of all elements that don't. The relative order of the elements in the resulting immutable hash sets is the same as in the original immutable hash set.

    Definition Classes
      TraversableLike → GenTraversableLike

93. #### def product: A

    [use case]

    [use case]
    returns

      the product of all elements in this immutable hash set of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the immutable hash set and as result type of `product`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

94. #### def reduce[A1 >: A](op: (A1, A1) ⇒ A1): A1

    Reduces the elements of this immutable hash set using the specified associative binary operator.

    Reduces the elements of this immutable hash set using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    A1

      A type parameter for the binary operator, a supertype of `A`.

    op

      A binary operator that must be associative.

    returns

      The result of applying reduce operator `op` between all the elements if the immutable hash set is nonempty.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Exceptions thrown
      UnsupportedOperationException

      if this immutable hash set is empty.

95. #### def reduceLeft[B >: A](op: (B, A) ⇒ B): B

    Definition Classes
      TraversableOnce

96. #### def reduceLeftOption[B >: A](op: (B, A) ⇒ B): Option[B]

    Optionally applies a binary operator to all elements of this immutable hash set, going left to right.

    Optionally applies a binary operator to all elements of this immutable hash set, going left to right.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    op

      the binary operator.

    returns

      an option value containing the result of `reduceLeft(op)` is this immutable hash set is nonempty, `None` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

97. #### def reduceOption[A1 >: A](op: (A1, A1) ⇒ A1): Option[A1]

    Reduces the elements of this immutable hash set, if any, using the specified associative binary operator.

    Reduces the elements of this immutable hash set, if any, using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    A1

      A type parameter for the binary operator, a supertype of `A`.

    op

      A binary operator that must be associative.

    returns

      An option value containing result of applying reduce operator `op` between all the elements if the collection is nonempty, and `None` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

98. #### def reduceRight[B >: A](op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this immutable hash set, going right to left.

    Applies a binary operator to all elements of this immutable hash set, going right to left.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this immutable hash set, going right to left:

                      op(x,,1,,, op(x,,2,,, ..., op(x,,n-1,,, x,,n,,)...))

      where `x1, ..., xn` are the elements of this immutable hash set.

    Definition Classes
      IterableLike → TraversableOnce → GenTraversableOnce
    Exceptions thrown
      `UnsupportedOperationException`

      if this immutable hash set is empty.

99. #### def reduceRightOption[B >: A](op: (A, B) ⇒ B): Option[B]

    Optionally applies a binary operator to all elements of this immutable hash set, going right to left.

    Optionally applies a binary operator to all elements of this immutable hash set, going right to left.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    op

      the binary operator.

    returns

      an option value containing the result of `reduceRight(op)` is this immutable hash set is nonempty, `None` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

100. #### def removed0(key: A, hash: Int, level: Int): HashSet[A]

     Attributes
       protected

101. #### def repr: HashSet[A]

     The collection of type immutable hash set underlying this `TraversableLike` object.

     The collection of type immutable hash set underlying this `TraversableLike` object. By default this is implemented as the `TraversableLike` object itself, but this can be overridden.

     Definition Classes
       TraversableLike → GenTraversableLike

102. #### def reversed: List[A]

     Attributes
       protected[this]
     Definition Classes
       TraversableOnce

103. #### def sameElements(that: GenIterable[A]): Boolean

     [use case]

     [use case]
     that

       the collection to compare with.

     returns

       `true`, if both collections contain the same elements in the same order, `false` otherwise.

     Definition Classes
       IterableLike → GenIterableLike

104. #### def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[HashSet[A], B, That]): That

     Computes a prefix scan of the elements of the collection.

     Computes a prefix scan of the elements of the collection.

     Note: The neutral element `z` may be applied more than once.

     B

       element type of the resulting collection

     That

       type of the resulting collection

     z

       neutral element for the operator `op`

     op

       the associative operator for the scan

     cbf

       combiner factory which provides a combiner

     returns

       a new immutable hash set containing the prefix scan of the elements in this immutable hash set

     Definition Classes
       TraversableLike → GenTraversableLike

105. #### def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[HashSet[A], B, That]): That

     Produces a collection containing cummulative results of applying the operator going left to right.

     Produces a collection containing cummulative results of applying the operator going left to right.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     B

       the type of the elements in the resulting collection

     That

       the actual type of the resulting collection

     z

       the initial value

     op

       the binary operator applied to the intermediate result and the element

     bf

       an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

     returns

       collection with intermediate results

     Definition Classes
       TraversableLike → GenTraversableLike

106. #### def scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[HashSet[A], B, That]): That

     Produces a collection containing cummulative results of applying the operator going right to left.

     Produces a collection containing cummulative results of applying the operator going right to left. The head of the collection is the last cummulative result.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     Example:

            List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)

     B

       the type of the elements in the resulting collection

     That

       the actual type of the resulting collection

     z

       the initial value

     op

       the binary operator applied to the intermediate result and the element

     bf

       an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

     returns

       collection with intermediate results

     Definition Classes
       TraversableLike → GenTraversableLike
     Annotations
       @migration
     Migration

       (Changed in version 2.9.0) The behavior of `scanRight` has changed. The previous behavior can be reproduced with scanRight.reverse.

107. #### def seq: Set[A]

     A version of this collection with all of the operations implemented sequentially (i.

     A version of this collection with all of the operations implemented sequentially (i.e. in a single-threaded manner).

     This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.

     returns

       a sequential view of the collection.

     Definition Classes
       Set → Set → GenSet → GenSetLike → Iterable → Iterable → GenIterable → Traversable → Traversable → GenTraversable → Parallelizable → TraversableOnce → GenTraversableOnce

108. #### def size: Int

     The size of this immutable hash set.

     The size of this immutable hash set.

     returns

       the number of elements in this immutable hash set.

     Definition Classes
       HashSet → GenTraversableLike → TraversableOnce → GenTraversableOnce

109. #### def slice(from: Int, until: Int): HashSet[A]

     Selects an interval of elements.

     Selects an interval of elements. The returned collection is made up of all elements `x` which satisfy the invariant:

            from <= indexOf(x) < until

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     from

       the lowest index to include from this immutable hash set.

     until

       the highest index to EXCLUDE from this immutable hash set.

     returns

       a immutable hash set containing the elements greater than or equal to index `from` extending up to (but not including) index `until` of this immutable hash set.

     Definition Classes
       IterableLike → TraversableLike → GenTraversableLike

110. #### def sliding(size: Int, step: Int): Iterator[HashSet[A]]

     Definition Classes
       IterableLike

111. #### def sliding(size: Int): Iterator[HashSet[A]]

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

     size

       the number of elements per group

     returns

       An iterator producing immutable hash sets of size `size`, except the last and the only element will be truncated if there are fewer elements than size.

     Definition Classes
       IterableLike
     See also

       Iterator#sliding

112. #### def span(p: (A) ⇒ Boolean): (HashSet[A], HashSet[A])

     Splits this immutable hash set into a prefix/suffix pair according to a predicate.

     Splits this immutable hash set into a prefix/suffix pair according to a predicate.

     Note: `c span p` is equivalent to (but possibly more efficient than) `(c takeWhile p, c dropWhile p)`, provided the evaluation of the predicate `p` does not cause any side-effects.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     p

       the test predicate

     returns

       a pair consisting of the longest prefix of this immutable hash set whose elements all satisfy `p`, and the rest of this immutable hash set.

     Definition Classes
       TraversableLike → GenTraversableLike

113. #### def splitAt(n: Int): (HashSet[A], HashSet[A])

     Splits this immutable hash set into two at a given position.

     Splits this immutable hash set into two at a given position. Note: `c splitAt n` is equivalent to (but possibly more efficient than) `(c take n, c drop n)`.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       the position at which to split.

     returns

       a pair of immutable hash sets consisting of the first `n` elements of this immutable hash set, and the other elements.

     Definition Classes
       TraversableLike → GenTraversableLike

114. #### def stringPrefix: String

     Defines the prefix of this object's `toString` representation.

     Defines the prefix of this object's `toString` representation.

     returns

       a string representation which starts the result of `toString` applied to this set. Unless overridden this is simply `"Set"`.

     Definition Classes
       SetLike → TraversableLike → GenTraversableLike

115. #### def subsetOf(that: GenSet[A]): Boolean

     Tests whether this set is a subset of another set.

     Tests whether this set is a subset of another set.

     that

       the set to test.

     returns

       `true` if this set is a subset of `that`, i.e. if every element of this set is also an element of `that`.

     Definition Classes
       GenSetLike

116. #### def subsets: Iterator[HashSet[A]]

     An iterator over all subsets of this set.

     An iterator over all subsets of this set.

     returns

       the iterator.

     Definition Classes
       SetLike

117. #### def subsets(len: Int): Iterator[HashSet[A]]

     An iterator over all subsets of this set of the given size.

     An iterator over all subsets of this set of the given size. If the requested size is impossible, an empty iterator is returned.

     len

       the size of the subsets.

     returns

       the iterator.

     Definition Classes
       SetLike

118. #### def sum: A

     [use case]

     [use case]
     returns

       the sum of all elements in this immutable hash set of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the immutable hash set and as result type of `sum`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

     Definition Classes
       TraversableOnce → GenTraversableOnce

119. #### final def synchronized[T0](arg0: ⇒ T0): T0

     Definition Classes
       AnyRef

120. #### def tail: HashSet[A]

     Selects all elements except the first.

     Selects all elements except the first.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       a immutable hash set consisting of all elements of this immutable hash set except the first one.

     Definition Classes
       TraversableLike → GenTraversableLike
     Exceptions thrown
       `UnsupportedOperationException`

       if the immutable hash set is empty.

121. #### def tails: Iterator[HashSet[A]]

     Iterates over the tails of this immutable hash set.

     Iterates over the tails of this immutable hash set. The first value will be this immutable hash set and the final one will be an empty immutable hash set, with the intervening values the results of successive applications of `tail`.

     returns

       an iterator over all the tails of this immutable hash set

     Definition Classes
       TraversableLike
     Example:

     1. `List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)`

122. #### def take(n: Int): HashSet[A]

     Selects first n elements.

     Selects first n elements.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       Tt number of elements to take from this immutable hash set.

     returns

       a immutable hash set consisting only of the first `n` elements of this immutable hash set, or else the whole immutable hash set, if it has less than `n` elements.

     Definition Classes
       IterableLike → TraversableLike → GenTraversableLike

123. #### def takeRight(n: Int): HashSet[A]

     Selects last n elements.

     Selects last n elements.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       the number of elements to take

     returns

       a immutable hash set consisting only of the last `n` elements of this immutable hash set, or else the whole immutable hash set, if it has less than `n` elements.

     Definition Classes
       IterableLike

124. #### def takeWhile(p: (A) ⇒ Boolean): HashSet[A]

     Takes longest prefix of elements that satisfy a predicate.

     Takes longest prefix of elements that satisfy a predicate.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     p

       The predicate used to test elements.

     returns

       the longest prefix of this immutable hash set whose elements all satisfy the predicate `p`.

     Definition Classes
       IterableLike → TraversableLike → GenTraversableLike

125. #### def thisCollection: Iterable[A]

     The underlying collection seen as an instance of `immutable.HashSet`.

     The underlying collection seen as an instance of `immutable.HashSet`. By default this is implemented as the current collection object itself, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       IterableLike → TraversableLike

126. #### def toArray: Array[A]

     [use case]

     [use case]
     returns

       an array containing all elements of this immutable hash set. A `ClassManifest` must be available for the element type of this immutable hash set.

     Definition Classes
       TraversableOnce → GenTraversableOnce

127. #### def toBuffer[A1 >: A]: Buffer[A1]

     Converts this immutable hash set to a mutable buffer.

     Converts this immutable hash set to a mutable buffer.

     returns

       a buffer containing all elements of this immutable hash set.

     Definition Classes
       SetLike → TraversableOnce → GenTraversableOnce

128. #### def toCollection(repr: HashSet[A]): Iterable[A]

     A conversion from collections of type `Repr` to `immutable.HashSet` objects.

     A conversion from collections of type `Repr` to `immutable.HashSet` objects. By default this is implemented as just a cast, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       IterableLike → TraversableLike

129. #### def toIndexedSeq: IndexedSeq[A]

     Converts this immutable hash set to an indexed sequence.

     Converts this immutable hash set to an indexed sequence.

     returns

       an indexed sequence containing all elements of this immutable hash set.

     Definition Classes
       TraversableOnce → GenTraversableOnce

130. #### def toIterable: Iterable[A]

     Converts this immutable hash set to an iterable collection.

     Converts this immutable hash set to an iterable collection. Note that the choice of target `Iterable` is lazy in this default implementation as this `TraversableOnce` may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

     returns

       an `Iterable` containing all elements of this immutable hash set.

     Definition Classes
       IterableLike → TraversableOnce → GenTraversableOnce

131. #### def toIterator: Iterator[A]

     Returns an Iterator over the elements in this immutable hash set.

     Returns an Iterator over the elements in this immutable hash set. Will return the same Iterator if this instance is already an Iterator.

     returns

       an Iterator containing all elements of this immutable hash set.

     Definition Classes
       IterableLike → TraversableLike → GenTraversableOnce

132. #### def toList: List[A]

     Converts this immutable hash set to a list.

     Converts this immutable hash set to a list.

     returns

       a list containing all elements of this immutable hash set.

     Definition Classes
       TraversableOnce → GenTraversableOnce

133. #### def toMap[T, U]: Map[T, U]

     [use case]

     [use case]
     returns

       a map of type `immutable.Map[T, U]` containing all key/value pairs of type `(T, U)` of this immutable hash set.

     Definition Classes
       TraversableOnce → GenTraversableOnce

134. #### def toSeq: Seq[A]

     Overridden for efficiency.

     Overridden for efficiency.

     returns

       a sequence containing all elements of this immutable hash set.

     Definition Classes
       SetLike → TraversableOnce → GenTraversableOnce

135. #### def toSet[B >: A]: Set[B]

     Converts this immutable hash set to a set.

     Converts this immutable hash set to a set.

     returns

       a set containing all elements of this immutable hash set.

     Definition Classes
       Set → TraversableOnce → GenTraversableOnce

136. #### def toStream: Stream[A]

     Converts this immutable hash set to a stream.

     Converts this immutable hash set to a stream.

     returns

       a stream containing all elements of this immutable hash set.

     Definition Classes
       IterableLike → TraversableLike → GenTraversableOnce

137. #### def toString(): String

     Creates a String representation of this object.

     Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

     returns

       a String representation of the object.

     Definition Classes
       SetLike → Function1 → TraversableLike → AnyRef → Any

138. #### def toTraversable: Traversable[A]

     Converts this immutable hash set to an unspecified Traversable.

     Converts this immutable hash set to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

     returns

       a Traversable containing all elements of this immutable hash set.

     Definition Classes
       TraversableLike → TraversableOnce → GenTraversableOnce

139. #### def union(that: GenSet[A]): HashSet[A]

     Computes the union between of set and another set.

     Computes the union between of set and another set.

     that

       the set to form the union with.

     returns

       a new set consisting of all elements that are in this set or in the given set `that`.

     Definition Classes
       SetLike → GenSetLike

140. #### def unzip[A1, A2](implicit asPair: (A) ⇒ (A1, A2)): (HashSet[A1], HashSet[A2])

     Converts this immutable hash set of pairs into two collections of the first and second half of each pair.

     Converts this immutable hash set of pairs into two collections of the first and second half of each pair.

     asPair

       an implicit conversion which asserts that the element type of this immutable hash set is a pair.

     returns

       a pair immutable hash sets, containing the first, respectively second half of each element pair of this immutable hash set.

     Definition Classes
       GenericTraversableTemplate

141. #### def unzip3[A1, A2, A3](implicit asTriple: (A) ⇒ (A1, A2, A3)): (HashSet[A1], HashSet[A2], HashSet[A3])

     Converts this immutable hash set of triples into three collections of the first, second, and third element of each triple.

     Converts this immutable hash set of triples into three collections of the first, second, and third element of each triple.

     asTriple

       an implicit conversion which asserts that the element type of this immutable hash set is a triple.

     returns

       a triple immutable hash sets, containing the first, second, respectively third member of each element triple of this immutable hash set.

     Definition Classes
       GenericTraversableTemplate

142. #### def updated0(key: A, hash: Int, level: Int): HashSet[A]

143. #### def view(from: Int, until: Int): IterableView[A, HashSet[A]]

     Creates a non-strict view of a slice of this immutable hash set.

     Creates a non-strict view of a slice of this immutable hash set.

     Note: the difference between `view` and `slice` is that `view` produces a view of the current immutable hash set, whereas `slice` produces a new immutable hash set.

     Note: `view(from, to)` is equivalent to `view.slice(from, to)`

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     from

       the index of the first element of the view

     until

       the index of the element following the view

     returns

       a non-strict view of a slice of this immutable hash set, starting at index `from` and extending up to (but not including) index `until`.

     Definition Classes
       IterableLike → TraversableLike

144. #### def view: IterableView[A, HashSet[A]]

     Creates a non-strict view of this immutable hash set.

     Creates a non-strict view of this immutable hash set.

     returns

       a non-strict view of this immutable hash set.

     Definition Classes
       IterableLike → TraversableLike

145. #### final def wait(): Unit

     Definition Classes
       AnyRef
     Annotations
       @throws()

146. #### final def wait(arg0: Long, arg1: Int): Unit

     Definition Classes
       AnyRef
     Annotations
       @throws()

147. #### final def wait(arg0: Long): Unit

     Definition Classes
       AnyRef
     Annotations
       @throws()

148. #### def withFilter(p: (A) ⇒ Boolean): FilterMonadic[A, HashSet[A]]

     Creates a non-strict filter of this immutable hash set.

     Creates a non-strict filter of this immutable hash set.

     Note: the difference between `c filter p` and `c withFilter p` is that the former creates a new collection, whereas the latter only restricts the domain of subsequent `map`, `flatMap`, `foreach`, and `withFilter` operations.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     p

       the predicate used to test elements.

     returns

       an object of class `WithFilter`, which supports `map`, `flatMap`, `foreach`, and `withFilter` operations. All these operations apply to those elements of this immutable hash set which satisfy the predicate `p`.

     Definition Classes
       TraversableLike → FilterMonadic

149. #### def writeReplace(): AnyRef

     Attributes
       protected

150. #### def zip[B](that: GenIterable[B]): immutable.HashSet[(A, B)]

     [use case]

     [use case]
     B

       the type of the second half of the returned pairs

     that

       The iterable providing the second half of each result pair

     returns

       a new immutable hash set containing pairs consisting of corresponding elements of this immutable hash set and `that`. The length of the returned collection is the minimum of the lengths of this immutable hash set and `that`.

     Definition Classes
       IterableLike → GenIterableLike

151. #### def zipAll[B](that: Iterable[B], thisElem: A, thatElem: B): immutable.HashSet[(A, B)]

     [use case]

     [use case]
     B

       the type of the second half of the returned pairs

     that

       The iterable providing the second half of each result pair

     thisElem

       the element to be used to fill up the result if this immutable hash set is shorter than `that`.

     thatElem

       the element to be used to fill up the result if `that` is shorter than this immutable hash set.

     returns

       a new immutable hash set containing pairs consisting of corresponding elements of this immutable hash set and `that`. The length of the returned collection is the maximum of the lengths of this immutable hash set and `that`. If this immutable hash set is shorter than `that`, `thisElem` values are used to pad the result. If `that` is shorter than this immutable hash set, `thatElem` values are used to pad the result.

     Definition Classes
       IterableLike → GenIterableLike

152. #### def zipWithIndex: immutable.HashSet[(A, Int)]

     [use case]

     [use case]
     returns

       A new immutable hash set containing pairs consisting of all elements of this immutable hash set paired with their index. Indices start at `0`. @example `List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))`

     Definition Classes
       IterableLike → GenIterableLike

153. #### def |(that: GenSet[A]): HashSet[A]

     Computes the union between this set and another set.

     Computes the union between this set and another set.

     Note: Same as `union`.

     that

       the set to form the union with.

     returns

       a new set consisting of all elements that are in this set or in the given set `that`.

     Definition Classes
       GenSetLike

### Inherited from Serializable

### Inherited from CustomParallelizable[A, ParHashSet[A]]

### Inherited from Set[A]

### Inherited from Iterable[A]

### Inherited from Traversable[A]

### Inherited from Immutable

### Inherited from AbstractSet[A]

### Inherited from Set[A]

### Inherited from SetLike[A, HashSet[A]]

### Inherited from Subtractable[A, HashSet[A]]

### Inherited from GenSet[A]

### Inherited from GenericSetTemplate[A, HashSet]

### Inherited from GenSetLike[A, HashSet[A]]

### Inherited from (A) ⇒ Boolean

### Inherited from AbstractIterable[A]

### Inherited from Iterable[A]

### Inherited from IterableLike[A, HashSet[A]]

### Inherited from Equals

### Inherited from GenIterable[A]

### Inherited from GenIterableLike[A, HashSet[A]]

### Inherited from AbstractTraversable[A]

### Inherited from Traversable[A]

### Inherited from GenTraversable[A]

### Inherited from GenericTraversableTemplate[A, HashSet]

### Inherited from TraversableLike[A, HashSet[A]]

### Inherited from GenTraversableLike[A, HashSet[A]]

### Inherited from Parallelizable[A, ParHashSet[A]]

### Inherited from TraversableOnce[A]

### Inherited from GenTraversableOnce[A]

### Inherited from FilterMonadic[A, HashSet[A]]

### Inherited from HasNewBuilder[A, HashSet[A]]

### Inherited from AnyRef

### Inherited from Any