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/Scala 2.12 Library

Trait scala.collection.immutable.Set

Companion object Set

trait Set[A] extends Iterable[A] with collection.Set[A] with GenericSetTemplate[A, Set] with SetLike[A, Set[A]] with Parallelizable[A, ParSet[A]]

A generic trait for immutable sets.

A set is a collection that contains no duplicate elements.

To implement a concrete set, you need to provide implementations of the following methods:

def contains(key: A): Boolean
def iterator: Iterator[A]
def +(elem: A): This
def -(elem: A): This

If you wish that methods like take, drop, filter return the same kind of set, you should also override:

def empty: This

It is also good idea to override methods foreach and size for efficiency.

Source
Set.scala
Since

1.0

Linear Supertypes
Known Subclasses

Type Members

class WithFilter extends FilterMonadic[A, Repr]

A class supporting filtered operations. Instances of this class are returned by method withFilter.

Definition Classes
TraversableLike

type Self = Set[A]

The type implementing this traversable

Attributes
protected[this]
Definition Classes
TraversableLike

Abstract Value Members

abstract def +(elem: A): Set[A]

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

elem

the element to be added

returns

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

Definition Classes
SetLikeGenSetLike

abstract def -(elem: A): Set[A]

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

elem

the element to be removed

returns

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

Definition Classes
SetLikeSubtractableGenSetLike

abstract def contains(elem: A): Boolean

Tests if some element is contained in this set.

elem

the element to test for membership.

returns

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

Definition Classes
SetLikeGenSetLike

abstract def iterator: Iterator[A]

Definition Classes
GenSetLikeGenIterableLike

Concrete Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns

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

Definition Classes
AnyRef → Any

final def ##(): Int

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

def &(that: GenSet[A]): Set[A]

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

def &~(that: GenSet[A]): Set[A]

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

def +(elem1: A, elem2: A, elems: A*): Set[A]

Creates a new set with additional elements, omitting duplicates.

This method takes two or more elements to be added. Elements that already exist in the set will not be added. Another overloaded variant of this method handles the case where a single element is added.

Example:

scala> val a = Set(1, 3) + 2 + 3
a: scala.collection.immutable.Set[Int] = Set(1, 3, 2)
elem1

the first element to add.

elem2

the second element to add.

elems

the remaining elements to add.

returns

a new set with the given elements added, omitting duplicates.

Definition Classes
SetLike

def ++(elems: GenTraversableOnce[A]): Set[A]

Creates a new set by adding all elements contained in another collection to this set, omitting duplicates.

This method takes a collection of elements and adds all elements, omitting duplicates, into set.

Example:

scala> val a = Set(1, 2) ++ Set(2, "a")
a: scala.collection.immutable.Set[Any] = Set(1, 2, a)
elems

the collection containing the elements to add.

returns

a new set with the given elements added, omitting duplicates.

Definition Classes
SetLike

def ++[B >: A, That](that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Set[A], B, That]): That

Returns a new traversable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the traversable collection is the most specific superclass encompassing the element types of the two operands.

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 the new element type B.

returns

a new collection of type That which contains all elements of this traversable collection followed by all elements of that.

Definition Classes
TraversableLikeGenTraversableLike

def ++:[B >: A, That](that: collection.Traversable[B])(implicit bf: CanBuildFrom[Set[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.

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 the new element type B.

returns

a new collection of type That which contains all elements of this traversable collection followed by all elements of that.

Definition Classes
TraversableLike

def ++:[B](that: TraversableOnce[B]): Set[B]

[use case]

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)
B

the element type of the returned collection.

that

the traversable to append.

returns

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

Definition Classes
TraversableLike
Full Signature

def -(elem1: A, elem2: A, elems: A*): Set[A]

Creates a new collection from this collection 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 collection that contains all elements of the current collection except one less occurrence of each of the given elements.

Definition Classes
Subtractable

def --(xs: GenTraversableOnce[A]): Set[A]

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

xs

the collection containing the removed elements.

returns

a new collection that contains all elements of the current collection except one less occurrence of each of the elements of elems.

Definition Classes
Subtractable

def ->[B](y: B): (Set[A], B)

Implicit
This member is added by an implicit conversion from Set[A] to ArrowAssoc[Set[A]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

def /:[B](z: B)(op: (B, A) ⇒ B): B

Applies a binary operator to a start value and all elements of this traversable or iterator, 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 = List(1,2,3,4)
a: List[Int] = List(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: will not terminate for infinite-sized collections.

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 traversable or iterator, going left to right with the start value z on the left:

op(...op(op(z, x_1), x_2), ..., x_n)

where x1, ..., xn are the elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

def :\[B](z: B)(op: (A, B) ⇒ B): B

Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.

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

Note: will not terminate for infinite-sized collections.

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 = List(1,2,3,4)
a: List[Int] = List(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 traversable or iterator, going right to left with the start value z on the right:

op(x_1, op(x_2, ... op(x_n, z)...))

where x1, ..., xn are the elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

final def ==(arg0: Any): Boolean

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
AnyRef → Any

def addString(b: StringBuilder): StringBuilder

Appends all elements of this traversable or iterator to a string builder. The written text consists of the string representations (w.r.t. the method toString) of all elements of this traversable or iterator without any separator string.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

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

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

the string builder to which elements are appended.

returns

the string builder b to which elements were appended.

Definition Classes
TraversableOnce

def addString(b: StringBuilder, sep: String): StringBuilder

Appends all elements of this traversable or iterator 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 traversable or iterator, separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(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

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

Appends all elements of this traversable or iterator 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 traversable or iterator are separated by the string sep.

Example:

scala> val a = List(1,2,3,4)
a: List[Int] = List(1, 2, 3, 4)

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

scala> a.addString(b , "List(" , ", " , ")")
res5: StringBuilder = List(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

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

Aggregates the results of applying an operator to subsequent elements.

This is a more general form of fold and reduce. It is similar to foldLeft in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.

aggregate splits the traversable or iterator into partitions and processes each partition by sequentially applying seqop, starting with z (like foldLeft). Those intermediate results are then combined by using combop (like fold). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), so combop may be invoked an arbitrary number of times (even 0).

As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First, seqop transforms each input character to an Int and adds it to the sum (of the partition). Then, combop just needs to sum up the intermediate results of the partitions:

List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
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) and may be evaluated more than once

seqop

an operator used to accumulate results within a partition

combop

an associative operator used to combine results from different partitions

Definition Classes
TraversableOnceGenTraversableOnce

def andThen[A](g: (Boolean) ⇒ A): (A) ⇒ A

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
Annotations
@unspecialized()

def apply(elem: A): Boolean

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
GenSetLikeFunction1

final def asInstanceOf[T0]: 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.

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.

that

The object with which this iterable collection should be compared

returns

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

Definition Classes
IterableLikeEquals

def clone(): AnyRef

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( ... ) @native()
Note

not specified by SLS as a member of AnyRef

def collect[B](pf: PartialFunction[A, B]): Set[B]

[use case]

Builds a new collection by applying a partial function to all elements of this immutable set on which the function is defined.

B

the element type of the returned collection.

pf

the partial function which filters and maps the immutable set.

returns

a new immutable 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
TraversableLikeGenTraversableLike
Full Signature

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

Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.

Note: may not terminate for infinite-sized collections.

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:

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

def companion: GenericCompanion[Set]

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

Definition Classes
SetSetGenSetIterableIterableGenIterableTraversableTraversableGenTraversableGenericTraversableTemplate

def compose[A](g: (A) ⇒ A): (A) ⇒ Boolean

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
Annotations
@unspecialized()

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

[use case]

Copies the elements of this immutable set to an array. Fills the given array xs with at most len elements of this immutable set, starting at position start. Copying will stop once either the end of the current immutable set is reached, or the end of the target array is reached, or len elements have been copied.

xs

the array to fill.

start

the starting index.

len

the maximal number of elements to copy.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
Full Signature

def copyToArray(xs: Array[A]): Unit

[use case]

Copies the elements of this immutable set to an array. Fills the given array xs with values of this immutable set. Copying will stop once either the end of the current immutable set is reached, or the end of the target array is reached.

xs

the array to fill.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

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

[use case]

Copies the elements of this immutable set to an array. Fills the given array xs with values of this immutable set, beginning at index start. Copying will stop once either the end of the current immutable set is reached, or the end of the target array is reached.

xs

the array to fill.

start

the starting index.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

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

Copies all elements of this traversable or iterator to a buffer.

Note: will not terminate for infinite-sized collections.

dest

The buffer to which elements are copied.

Definition Classes
TraversableOnce

def count(p: (A) ⇒ Boolean): Int

Counts the number of elements in the traversable or iterator which satisfy a predicate.

p

the predicate used to test elements.

returns

the number of elements satisfying the predicate p.

Definition Classes
TraversableOnceGenTraversableOnce

def diff(that: GenSet[A]): Set[A]

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
SetLikeGenSetLike

def drop(n: Int): Set[A]

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 iterable collection.

returns

a iterable collection consisting of all elements of this iterable collection except the first n ones, or else the empty iterable collection, if this iterable collection has less than n elements. If n is negative, don't drop any elements.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike

def dropRight(n: Int): Set[A]

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 iterable collection consisting of all elements of this iterable collection except the last n ones, or else the empty iterable collection, if this iterable collection has less than n elements.

Definition Classes
IterableLike

def dropWhile(p: (A) ⇒ Boolean): Set[A]

Drops longest prefix of elements that satisfy a predicate.

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

returns

the longest suffix of this traversable collection whose first element does not satisfy the predicate p.

Definition Classes
TraversableLikeGenTraversableLike

def empty: Set[A]

Definition Classes
GenericSetTemplate

def ensuring(cond: (Set[A]) ⇒ Boolean, msg: ⇒ Any): Set[A]

Implicit
This member is added by an implicit conversion from Set[A] to Ensuring[Set[A]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (Set[A]) ⇒ Boolean): Set[A]

Implicit
This member is added by an implicit conversion from Set[A] to Ensuring[Set[A]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: ⇒ Any): Set[A]

Implicit
This member is added by an implicit conversion from Set[A] to Ensuring[Set[A]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): Set[A]

Implicit
This member is added by an implicit conversion from Set[A] to Ensuring[Set[A]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) 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

def equals(that: Any): Boolean

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
GenSetLikeEquals → AnyRef → Any

def exists(p: (A) ⇒ Boolean): Boolean

Tests whether a predicate holds for at least one element of this iterable collection.

Note: may not terminate for infinite-sized collections.

p

the predicate used to test elements.

returns

false if this iterable collection is empty, otherwise true if the given predicate p holds for some of the elements of this iterable collection, otherwise false

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce

def filter(p: (A) ⇒ Boolean): Set[A]

Selects all elements of this traversable collection which satisfy a predicate.

p

the predicate used to test elements.

returns

a new traversable collection consisting of all elements of this traversable collection that satisfy the given predicate p. The order of the elements is preserved.

Definition Classes
TraversableLikeGenTraversableLike

def filterNot(p: (A) ⇒ Boolean): Set[A]

Selects all elements of this traversable collection which do not satisfy a predicate.

p

the predicate used to test elements.

returns

a new traversable collection consisting of all elements of this traversable collection that do not satisfy the given predicate p. The order of the elements is preserved.

Definition Classes
TraversableLikeGenTraversableLike

def finalize(): Unit

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( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

def find(p: (A) ⇒ Boolean): Option[A]

Finds the first element of the iterable collection satisfying a predicate, if any.

Note: may not terminate for infinite-sized collections.

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 iterable collection that satisfies p, or None if none exists.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce

def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Set[B]

[use case]

Builds a new collection by applying a function to all elements of this immutable set and using the elements of the resulting collections.

For example:

def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

The type of the resulting collection is guided by the static type of immutable set. This might cause unexpected results sometimes. For example:

// lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)

// lettersOf will return a Set[Char], not a Seq
def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq)

// xs will be an Iterable[Int]
val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)

// ys will be a Map[Int, Int]
val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
B

the element type of the returned collection.

f

the function to apply to each element.

returns

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

Definition Classes
TraversableLikeGenTraversableLikeFilterMonadic
Full Signature

def flatten[B]: Set[B]

[use case]

Converts this immutable set of traversable collections into a immutable set formed by the elements of these traversable collections.

The resulting collection's type will be guided by the static type of immutable set. For example:

val xs = List(
           Set(1, 2, 3),
           Set(1, 2, 3)
         ).flatten
// xs == List(1, 2, 3, 1, 2, 3)

val ys = Set(
           List(1, 2, 3),
           List(3, 2, 1)
         ).flatten
// ys == Set(1, 2, 3)
B

the type of the elements of each traversable collection.

returns

a new immutable set resulting from concatenating all element immutable sets.

Definition Classes
GenericTraversableTemplate
Full Signature

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

Folds the elements of this traversable or iterator using the specified associative binary operator.

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

Note: will not terminate for infinite-sized collections.

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 the fold operator op between all the elements and z, or z if this traversable or iterator is empty.

Definition Classes
TraversableOnceGenTraversableOnce

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

Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.

Note: will not terminate for infinite-sized collections.

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 traversable or iterator, going left to right with the start value z on the left:

op(...op(z, x_1), x_2, ..., x_n)

where x1, ..., xn are the elements of this traversable or iterator. Returns z if this traversable or iterator is empty.

Definition Classes
TraversableOnceGenTraversableOnce

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

Applies a binary operator to all elements of this iterable collection and a start value, going right to left.

Note: will not terminate for infinite-sized collections.

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 iterable collection, going right to left with the start value z on the right:

op(x_1, op(x_2, ... op(x_n, z)...))

where x1, ..., xn are the elements of this iterable collection. Returns z if this iterable collection is empty.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce

def forall(p: (A) ⇒ Boolean): Boolean

Tests whether a predicate holds for all elements of this iterable collection.

Note: may not terminate for infinite-sized collections.

p

the predicate used to test elements.

returns

true if this iterable collection is empty or the given predicate p holds for all elements of this iterable collection, otherwise false.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce

def foreach(f: (A) ⇒ Unit): Unit

[use case]

Applies a function f to all elements of this immutable set.

Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.

f

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

Definition Classes
IterableLikeTraversableLikeGenTraversableLikeTraversableOnceGenTraversableOnceFilterMonadic
Full Signature

def formatted(fmtstr: String): String

Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

Implicit
This member is added by an implicit conversion from Set[A] to StringFormat[Set[A]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

def genericBuilder[B]: Builder[B, Set[B]]

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

Definition Classes
GenericTraversableTemplate

final def getClass(): Class[_]

Returns the runtime class representation of the object.

returns

a class object corresponding to the runtime type of the receiver.

Definition Classes
AnyRef → Any
Annotations
@native()

def groupBy[K](f: (A) ⇒ K): Map[K, Set[A]]

Partitions this traversable collection into a map of traversable collections 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 traversable collection.

K

the type of keys returned by the discriminator function.

f

the discriminator function.

returns

A map from keys to traversable collections such that the following invariant holds:

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

That is, every key k is bound to a traversable collection of those elements x for which f(x) equals k.

Definition Classes
TraversableLikeGenTraversableLike

def grouped(size: Int): Iterator[Set[A]]

Partitions elements in fixed size iterable collections.

size

the number of elements per group

returns

An iterator producing iterable collections of size size, except the last will be less than size size if the elements don't divide evenly.

Definition Classes
IterableLike
See also

scala.collection.Iterator, method grouped

def hasDefiniteSize: Boolean

Tests whether this traversable collection 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. Non-empty Iterators usually return false even if they were created from a collection with a known finite size.

Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize returns true. However, checking hasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

returns

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

Definition Classes
TraversableLikeTraversableOnceGenTraversableOnce

def hashCode(): Int

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

returns

the hash code value for this object.

Definition Classes
GenSetLike → AnyRef → Any

Selects the first element of this iterable collection.

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

returns

the first element of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
Exceptions thrown

NoSuchElementException if the iterable collection is empty.

def headOption: Option[A]

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 traversable collection if it is nonempty, None if it is empty.

Definition Classes
TraversableLikeGenTraversableLike

def init: Set[A]

Selects all elements except the last.

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

returns

a traversable collection consisting of all elements of this traversable collection except the last one.

Definition Classes
TraversableLikeGenTraversableLike
Exceptions thrown

UnsupportedOperationException if the traversable collection is empty.

def inits: Iterator[Set[A]]

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

returns

an iterator over all the inits of this traversable collection

Definition Classes
TraversableLike
Example:

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

def intersect(that: GenSet[A]): Set[A]

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

def isEmpty: Boolean

Tests if this set is empty.

returns

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

Definition Classes
SetLikeIterableLikeTraversableLikeTraversableOnceGenTraversableOnce

final def isInstanceOf[T0]: Boolean

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

final def isTraversableAgain: Boolean

Tests whether this traversable collection can be repeatedly traversed.

returns

true

Definition Classes
TraversableLikeGenTraversableLikeGenTraversableOnce

def last: A

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 traversable collection.

Definition Classes
TraversableLikeGenTraversableLike
Exceptions thrown

NoSuchElementException If the traversable collection is empty.

def lastOption: Option[A]

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 traversable collection$ if it is nonempty, None if it is empty.

Definition Classes
TraversableLikeGenTraversableLike

def map[B](f: (A) ⇒ B): Set[B]

[use case]

Builds a new collection by applying a function to all elements of this immutable set.

B

the element type of the returned collection.

f

the function to apply to each element.

returns

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

Definition Classes
SetLikeTraversableLikeGenTraversableLikeFilterMonadic
Full Signature

def max: A

[use case]

Finds the largest element.

returns

the largest element of this immutable set.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature
Exceptions thrown

UnsupportedOperationException if this immutable set is empty.

def maxBy[B](f: (A) ⇒ B): A

[use case]

Finds the first element which yields the largest value measured by function f.

B

The result type of the function f.

f

The measuring function.

returns

the first element of this immutable set with the largest value measured by function f.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature
Exceptions thrown

UnsupportedOperationException if this immutable set is empty.

def min: A

[use case]

Finds the smallest element.

returns

the smallest element of this immutable set

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature
Exceptions thrown

UnsupportedOperationException if this immutable set is empty.

def minBy[B](f: (A) ⇒ B): A

[use case]

Finds the first element which yields the smallest value measured by function f.

B

The result type of the function f.

f

The measuring function.

returns

the first element of this immutable set with the smallest value measured by function f.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature
Exceptions thrown

UnsupportedOperationException if this immutable set is empty.

def mkString: String

Displays all elements of this traversable or iterator in a string.

returns

a string representation of this traversable or iterator. In the resulting string the string representations (w.r.t. the method toString) of all elements of this traversable or iterator follow each other without any separator string.

Definition Classes
TraversableOnceGenTraversableOnce

def mkString(sep: String): String

Displays all elements of this traversable or iterator in a string using a separator string.

sep

the separator string.

returns

a string representation of this traversable or iterator. In the resulting string the string representations (w.r.t. the method toString) of all elements of this traversable or iterator are separated by the string sep.

Definition Classes
TraversableOnceGenTraversableOnce
Example:

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

def mkString(start: String, sep: String, end: String): String

Displays all elements of this traversable or iterator 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 traversable or iterator. 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 traversable or iterator are separated by the string sep.

Definition Classes
TraversableOnceGenTraversableOnce
Example:

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

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns

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

Definition Classes
AnyRef

def newBuilder: Builder[A, Set[A]]

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

Attributes
protected[this]
Definition Classes
SetLikeTraversableLikeHasNewBuilder

def nonEmpty: Boolean

Tests whether the traversable or iterator is not empty.

returns

true if the traversable or iterator contains at least one element, false otherwise.

Definition Classes
TraversableOnceGenTraversableOnce

final def notify(): Unit

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

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

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

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

def par: ParSet[A]

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
Parallelizable

def parCombiner: Combiner[A, ParSet[A]]

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
Definition Classes
SetSetLikeIterableTraversableLikeParallelizable

def partition(p: (A) ⇒ Boolean): (Set[A], Set[A])

Partitions this traversable collection in two traversable collections according to a predicate.

p

the predicate on which to partition.

returns

a pair of traversable collections: the first traversable collection consists of all elements that satisfy the predicate p and the second traversable collection consists of all elements that don't. The relative order of the elements in the resulting traversable collections is the same as in the original traversable collection.

Definition Classes
TraversableLikeGenTraversableLike

def product: A

[use case]

Multiplies up the elements of this collection.

returns

the product of all elements in this immutable 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 set and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

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

Reduces the elements of this traversable or iterator 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 traversable or iterator is nonempty.

Definition Classes
TraversableOnceGenTraversableOnce
Exceptions thrown

UnsupportedOperationException if this traversable or iterator is empty.

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

Applies a binary operator to all elements of this traversable or iterator, going left to right.

Note: will not terminate for infinite-sized collections.

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 traversable or iterator, going left to right:

op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)

where x1, ..., xn are the elements of this traversable or iterator.

Definition Classes
TraversableOnce
Exceptions thrown

UnsupportedOperationException if this traversable or iterator is empty.

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

Optionally applies a binary operator to all elements of this traversable or iterator, going left to right.

Note: will not terminate for infinite-sized collections.

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) if this traversable or iterator is nonempty, None otherwise.

Definition Classes
TraversableOnceGenTraversableOnce

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

Reduces the elements of this traversable or iterator, 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
TraversableOnceGenTraversableOnce

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

Applies a binary operator to all elements of this iterable collection, going right to left.

Note: will not terminate for infinite-sized collections.

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 iterable collection, going right to left:

op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

where x1, ..., xn are the elements of this iterable collection.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce
Exceptions thrown

UnsupportedOperationException if this iterable collection is empty.

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

Optionally applies a binary operator to all elements of this traversable or iterator, going right to left.

Note: will not terminate for infinite-sized collections.

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) if this traversable or iterator is nonempty, None otherwise.

Definition Classes
TraversableOnceGenTraversableOnce

def repr: Set[A]

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

Definition Classes
TraversableLikeGenTraversableLike

def reversed: scala.List[A]

Attributes
protected[this]
Definition Classes
TraversableOnce

def sameElements(that: GenIterable[A]): Boolean

[use case]

Checks if the other iterable collection contains the same elements in the same order as this immutable set.

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

that

the collection to compare with.

returns

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

Definition Classes
IterableLikeGenIterableLike
Full Signature

def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Set[A], B, That]): That

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 traversable collection containing the prefix scan of the elements in this traversable collection

Definition Classes
TraversableLikeGenTraversableLike

def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[Set[A], B, That]): That

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

Note: will not terminate for infinite-sized collections.

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 the new element type B.

returns

collection with intermediate results

Definition Classes
TraversableLikeGenTraversableLike

def scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[Set[A], B, That]): That

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

Note: will not terminate for infinite-sized collections.

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 the new element type B.

returns

collection with intermediate results

Definition Classes
TraversableLikeGenTraversableLike
Annotations
@migration
Migration

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

def seq: Set[A]

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
SetSetGenSetGenSetLikeIterableIterableGenIterableTraversableTraversableGenTraversableParallelizableTraversableOnceGenTraversableOnce

def size: Int

The size of this traversable or iterator.

Note: will not terminate for infinite-sized collections.

returns

the number of elements in this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

def sizeHintIfCheap: Int

The size of this collection or iterator, if it can be cheaply computed

returns

the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply

Attributes
protected[collection]
Definition Classes
GenTraversableOnce

def slice(from: Int, until: Int): Set[A]

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.

returns

a iterable collection containing the elements greater than or equal to index from extending up to (but not including) index until of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike

def sliding(size: Int, step: Int): Iterator[Set[A]]

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

step

the distance between the first elements of successive groups

returns

An iterator producing iterable collections of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

Definition Classes
IterableLike
See also

scala.collection.Iterator, method sliding

def sliding(size: Int): Iterator[Set[A]]

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

size

the number of elements per group

returns

An iterator producing iterable collections of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

Definition Classes
IterableLike
See also

scala.collection.Iterator, method sliding

def span(p: (A) ⇒ Boolean): (Set[A], Set[A])

Splits this traversable collection 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.

returns

a pair consisting of the longest prefix of this traversable collection whose elements all satisfy p, and the rest of this traversable collection.

Definition Classes
TraversableLikeGenTraversableLike

def splitAt(n: Int): (Set[A], Set[A])

Splits this traversable collection 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 traversable collections consisting of the first n elements of this traversable collection, and the other elements.

Definition Classes
TraversableLikeGenTraversableLike

def stringPrefix: String

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
SetLikeTraversableLikeGenTraversableLike

def subsetOf(that: GenSet[A]): Boolean

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

def subsets(): Iterator[Set[A]]

An iterator over all subsets of this set.

returns

the iterator.

Definition Classes
SetLike

def subsets(len: Int): Iterator[Set[A]]

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

def sum: A

[use case]

Sums up the elements of this collection.

returns

the sum of all elements in this immutable 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 set and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef

def tail: Set[A]

Selects all elements except the first.

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

returns

a traversable collection consisting of all elements of this traversable collection except the first one.

Definition Classes
TraversableLikeGenTraversableLike
Exceptions thrown

java.lang.UnsupportedOperationException if the traversable collection is empty.

def tails: Iterator[Set[A]]

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

returns

an iterator over all the tails of this traversable collection

Definition Classes
TraversableLike
Example:

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

def take(n: Int): Set[A]

Selects first n elements.

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

n

the number of elements to take from this iterable collection.

returns

a iterable collection consisting only of the first n elements of this iterable collection, or else the whole iterable collection, if it has less than n elements. If n is negative, returns an empty iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike

def takeRight(n: Int): Set[A]

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 iterable collection consisting only of the last n elements of this iterable collection, or else the whole iterable collection, if it has less than n elements.

Definition Classes
IterableLike

def takeWhile(p: (A) ⇒ Boolean): Set[A]

Takes longest prefix of elements that satisfy a predicate.

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

returns

the longest prefix of this iterable collection whose elements all satisfy the predicate p.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike

def thisCollection: collection.Iterable[A]

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

Attributes
protected[this]
Definition Classes
IterableLikeTraversableLike

def to[Col[_]]: Col[A]

[use case]

Converts this immutable set into another by copying all elements.

Col

The collection type to build.

returns

a new collection containing all elements of this immutable set.

Definition Classes
TraversableLikeTraversableOnceGenTraversableOnce
Full Signature

def toArray: Array[A]

[use case]

Converts this immutable set to an array.

returns

an array containing all elements of this immutable set. An ClassTag must be available for the element type of this immutable set.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

def toBuffer[A1 >: A]: Buffer[A1]

Uses the contents of this set to create a new mutable buffer.

returns

a buffer containing all elements of this set.

Definition Classes
SetLikeTraversableOnceGenTraversableOnce

def toCollection(repr: Set[A]): collection.Iterable[A]

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

Attributes
protected[this]
Definition Classes
IterableLikeTraversableLike

def toIndexedSeq: IndexedSeq[A]

Converts this traversable or iterator to an indexed sequence.

Note: will not terminate for infinite-sized collections.

returns

an indexed sequence containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

def toIterable: collection.Iterable[A]

Returns this iterable collection as an iterable collection.

A new collection will not be built; lazy collections will stay lazy.

Note: will not terminate for infinite-sized collections.

returns

an Iterable containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce

def toIterator: Iterator[A]

Returns an Iterator over the elements in this iterable collection. Produces the same result as iterator.

Note: will not terminate for infinite-sized collections.

returns

an Iterator containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableOnce
Annotations
@deprecatedOverriding( message = ... , since = "2.11.0" )

def toList: scala.List[A]

Converts this traversable or iterator to a list.

Note: will not terminate for infinite-sized collections.

returns

a list containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

def toMap[T, U]: collection.Map[T, U]

[use case]

Converts this immutable set to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.

returns

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

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

def toParArray: ParArray[T]

Implicit
This member is added by an implicit conversion from Set[A] to CollectionsHaveToParArray[Set[A], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (Set[A]) ⇒ GenTraversableOnce[T] is in scope.
Definition Classes
CollectionsHaveToParArray

def toSeq: collection.Seq[A]

Converts this set to a sequence. As with toIterable, it's lazy in this default implementation, as this TraversableOnce may be lazy and unevaluated.

returns

a sequence containing all elements of this set.

Definition Classes
SetLikeTraversableOnceGenTraversableOnce

def toSet[B >: A]: Set[B]

Returns this immutable set as an immutable set, perhaps accepting a wider range of elements. Since it already is an immutable set, it will only be rebuilt if the underlying structure cannot be expanded to include arbitrary element types. For instance, BitSet and SortedSet will be rebuilt, as they require Int and sortable elements respectively.

When in doubt, the set will be rebuilt. Rebuilt sets never need to be rebuilt again.

returns

a set containing all elements of this immutable set.

Definition Classes
SetTraversableOnceGenTraversableOnce

def toStream: Stream[A]

Converts this iterable collection to a stream.

returns

a stream containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableOnce

def toString(): String

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
SetLikeFunction1TraversableLike → AnyRef → Any

def toTraversable: collection.Traversable[A]

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

Note: will not terminate for infinite-sized collections.

returns

a Traversable containing all elements of this traversable collection.

Definition Classes
TraversableLikeTraversableOnceGenTraversableOnce
Annotations
@deprecatedOverriding( message = ... , since = "2.11.0" )

def toVector: scala.Vector[A]

Converts this traversable or iterator to a Vector.

Note: will not terminate for infinite-sized collections.

returns

a vector containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce

def transpose[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): Set[Set[B]]

Transposes this collection of traversable collections into a collection of collections.

The resulting collection's type will be guided by the static type of collection. For example:

val xs = List(
           Set(1, 2, 3),
           Set(4, 5, 6)).transpose
// xs == List(
//         List(1, 4),
//         List(2, 5),
//         List(3, 6))

val ys = Vector(
           List(1, 2, 3),
           List(4, 5, 6)).transpose
// ys == Vector(
//         Vector(1, 4),
//         Vector(2, 5),
//         Vector(3, 6))
B

the type of the elements of each traversable collection.

asTraversable

an implicit conversion which asserts that the element type of this collection is a Traversable.

returns

a two-dimensional collection of collections which has as nth row the nth column of this collection.

Definition Classes
GenericTraversableTemplate
Annotations
@migration
Migration

(Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.

Exceptions thrown

IllegalArgumentException if all collections in this collection are not of the same size.

def union(that: GenSet[A]): Set[A]

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
SetLikeGenSetLike

def unzip[A1, A2](implicit asPair: (A) ⇒ (A1, A2)): (Set[A1], Set[A2])

Converts this collection of pairs into two collections of the first and second half of each pair.

val xs = Traversable(
           (1, "one"),
           (2, "two"),
           (3, "three")).unzip
// xs == (Traversable(1, 2, 3),
//        Traversable(one, two, three))
A1

the type of the first half of the element pairs

A2

the type of the second half of the element pairs

asPair

an implicit conversion which asserts that the element type of this collection is a pair.

returns

a pair of collections, containing the first, respectively second half of each element pair of this collection.

Definition Classes
GenericTraversableTemplate

def unzip3[A1, A2, A3](implicit asTriple: (A) ⇒ (A1, A2, A3)): (Set[A1], Set[A2], Set[A3])

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

val xs = Traversable(
           (1, "one", '1'),
           (2, "two", '2'),
           (3, "three", '3')).unzip3
// xs == (Traversable(1, 2, 3),
//        Traversable(one, two, three),
//        Traversable(1, 2, 3))
A1

the type of the first member of the element triples

A2

the type of the second member of the element triples

A3

the type of the third member of the element triples

asTriple

an implicit conversion which asserts that the element type of this collection is a triple.

returns

a triple of collections, containing the first, second, respectively third member of each element triple of this collection.

Definition Classes
GenericTraversableTemplate

def view(from: Int, until: Int): IterableView[A, Set[A]]

Creates a non-strict view of a slice of this iterable collection.

Note: the difference between view and slice is that view produces a view of the current iterable collection, whereas slice produces a new iterable collection.

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 iterable collection, starting at index from and extending up to (but not including) index until.

Definition Classes
IterableLikeTraversableLike

def view: IterableView[A, Set[A]]

Creates a non-strict view of this iterable collection.

returns

a non-strict view of this iterable collection.

Definition Classes
IterableLikeTraversableLike

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

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

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def withFilter(p: (A) ⇒ Boolean): FilterMonadic[A, Set[A]]

Creates a non-strict filter of this traversable collection.

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 traversable collection which satisfy the predicate p.

Definition Classes
TraversableLikeFilterMonadic

def zip[B](that: GenIterable[B]): Set[(A, B)]

[use case]

Returns a immutable set formed from this immutable set and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

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

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

Definition Classes
IterableLikeGenIterableLike
Full Signature

def zipAll[B](that: collection.Iterable[B], thisElem: A, thatElem: B): Set[(A, B)]

[use case]

Returns a immutable set formed from this immutable set and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

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

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 set is shorter than that.

thatElem

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

returns

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

Definition Classes
IterableLikeGenIterableLike
Full Signature

def zipWithIndex: Set[(A, Int)]

[use case]

Zips this immutable set with its indices.

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

returns

A new immutable set containing pairs consisting of all elements of this immutable set paired with their index. Indices start at 0.

Definition Classes
IterableLikeGenIterableLike
Full Signature
Example:

    List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))

def |(that: GenSet[A]): Set[A]

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

def [B](y: B): (Set[A], B)

Implicit
This member is added by an implicit conversion from Set[A] to ArrowAssoc[Set[A]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

Shadowed Implicit Value Members

def +(other: String): String

Implicit
This member is added by an implicit conversion from Set[A] to any2stringadd[Set[A]] performed by method any2stringadd in scala.Predef.
Shadowing
This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:
(set: any2stringadd[Set[A]]).+(other)
Definition Classes
any2stringadd

def filter(p: (A) ⇒ Boolean): TraversableOnce[A]

Implicit
This member is added by an implicit conversion from Set[A] to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
Shadowing
This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:
(set: MonadOps[A]).filter(p)
Definition Classes
MonadOps

def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): TraversableOnce[B]

Implicit
This member is added by an implicit conversion from Set[A] to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
Shadowing
This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:
(set: MonadOps[A]).flatMap(f)
Definition Classes
MonadOps

def map[B](f: (A) ⇒ B): TraversableOnce[B]

Implicit
This member is added by an implicit conversion from Set[A] to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
Shadowing
This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:
(set: MonadOps[A]).map(f)
Definition Classes
MonadOps

def withFilter(p: (A) ⇒ Boolean): Iterator[A]

Implicit
This member is added by an implicit conversion from Set[A] to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
Shadowing
This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:
(set: MonadOps[A]).withFilter(p)
Definition Classes
MonadOps

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/collection/immutable/Set.html