Scala Library
scala.collection.immutable

trait Set
[source: scala/collection/immutable/Set.scala]
trait Set[A]
extends Set[A]

This class defines the interface for immutable sets. Operations on an immutable set leave the original set unchanged, and return a new set if needed.

Concrete set implementations just have to provide functionality for the abstract methods in scala.collection.Set as well as for + and -.

Note that abstract immutable.Set's are not covariant in their type parameter. This is because some implementations cannot support the + method for arbitrary types.

Author
Matthias Zenger, Martin Odersky
Version
1.1, 03/05/2004
Direct Known Subclasses:
Enumeration.SetXX, EmptySet, HashSet, ListSet, Set1, Set2, Set3, Set4, SortedSet
Method Summary
override def ** (that : Set[A]) : Set[A]
This method is an alias for intersect. It computes an intersection with set that. It removes all the elements that are not present in that.
abstract def + (elem : A) : Set[A]
Create a new set with an additional element.
def + (elem1 : A, elem2 : A, elems : A*) : Set[A]
Add two or more elements to this set.
def ++ (elems : Iterator[A]) : Set[A]
Add all the elements provided by an iterator to the set.
def ++ (elems : Iterable[A]) : Set[A]
Add all the elements provided by an iterator of the iterable object elems to the set.
abstract def - (elem : A) : Set[A]
Remove a single element from a set.
def - (elem1 : A, elem2 : A, elems : A*) : Set[A]
Remove two or more elements from this set.
def -- (elems : Iterable[A]) : Set[A]
Remove all the elements provided by an iterator of the iterable object elems from the set.
def -- (elems : Iterator[A]) : Set[A]
Remove all the elements provided by an iterator elems from the set.
abstract def empty [B] : Set[B]
def excl (elems : A*) : Set[A]
excl removes many elements from the set.
def excl (that : Iterable[A]) : Set[A]
This method removes all the elements provided by an iterator of the iterable object that from the set.
override def filter (p : (A) => Boolean) : Set[A]
Method filter removes all elements from the set for which the predicate p yields the value false.
override def flatMap [B](f : (A) => Iterable[B]) : Set[B]
Applies the given function f to each element of this set, then forms the union of all results.
def incl (elems : A*) : Set[A]
incl can be used to add many elements to the set at the same time.
def incl (that : Iterable[A]) : Set[A]
This method will add all the elements provided by an iterator of the iterable object that to the set.
def intersect (that : Set[A]) : Set[A]
This method computes an intersection with set that. It removes all the elements that are not present in that.
override def map [B](f : (A) => B) : Set[B]
Returns the set resulting from applying the given function f to each element of this set.
Methods inherited from Set
size (abstract), contains (abstract), apply, isEmpty, subsetOf, *, equals, hashCode, toArray, stringPrefix
Methods inherited from Collection
toString
Methods inherited from Iterable
elements (abstract), concat, ++, partition, takeWhile, dropWhile, take, drop, foreach, forall, exists, find, findIndexOf, indexOf, foldLeft, foldRight, /:, :\, reduceLeft, reduceRight, copyToBuffer, sameElements, toList, toSeq, toStream, mkString, mkString, mkString, addString, addString, addString, copyToArray, projection, hasDefiniteSize
Methods inherited from Function1
compose, andThen
Methods inherited from AnyRef
getClass, clone, notify, notifyAll, wait, wait, wait, finalize, ==, !=, eq, ne, synchronized
Methods inherited from Any
==, !=, isInstanceOf, asInstanceOf
Method Details
abstract def empty[B] : Set[B]
Returns
an empty set of arbitrary element type
abstract def +(elem : A) : Set[A]
Create a new set with an additional element.
def +(elem1 : A, elem2 : A, elems : A*) : Set[A]
Add two or more elements to this set.
Parameters
elem1 - the first element.
elem2 - the second element.
elems - the remaining elements.
Returns
a new set with the elements added.
def ++(elems : Iterable[A]) : Set[A]
Add all the elements provided by an iterator of the iterable object elems to the set.
Parameters
elems - the iterable object containing the elements to be added
Returns
a new set with the elements added.
def ++(elems : Iterator[A]) : Set[A]
Add all the elements provided by an iterator to the set.
Parameters
elems - the iterator containing the elements to be added
Returns
a new set with the elements added.
@deprecated

def incl(elems : A*) : Set[A]
incl can be used to add many elements to the set at the same time.
Deprecated
use + instead
@deprecated

def incl(that : Iterable[A]) : Set[A]
This method will add all the elements provided by an iterator of the iterable object that to the set.
Deprecated
use ++ instead
abstract def -(elem : A) : Set[A]
Remove a single element from a set.
Parameters
elem - the element to be removed
Returns
a new set with the element removed.
def -(elem1 : A, elem2 : A, elems : A*) : Set[A]
Remove two or more elements from this set.
Parameters
elem1 - the first element.
elem2 - the second element.
elems - the remaining elements.
Returns
a new set with the elements removed.
def --(elems : Iterable[A]) : Set[A]
Remove all the elements provided by an iterator of the iterable object elems from the set.
Parameters
elems - An iterable object containing the elements to remove from the set.
Returns
a new set with the elements removed.
def --(elems : Iterator[A]) : Set[A]
Remove all the elements provided by an iterator elems from the set.
Parameters
elems - An iterator containing the elements to remove from the set.
Returns
a new set with the elements removed.
@deprecated

def excl(elems : A*) : Set[A]
excl removes many elements from the set.
@deprecated

def excl(that : Iterable[A]) : Set[A]
This method removes all the elements provided by an iterator of the iterable object that from the set.
Parameters
that - the iterable collection.
def intersect(that : Set[A]) : Set[A]
This method computes an intersection with set that. It removes all the elements that are not present in that.
Parameters
that - the set to intersect with.
override def **(that : Set[A]) : Set[A]
This method is an alias for intersect. It computes an intersection with set that. It removes all the elements that are not present in that.
Parameters
that - the set to intersect with
Overrides
Set.**
override def map[B](f : (A) => B) : Set[B]
Returns the set resulting from applying the given function f to each element of this set.
Parameters
f - function to apply to each element.
Returns
a set containing f(a0), ..., f(an) if this set contains a0, ..., an.
override def flatMap[B](f : (A) => Iterable[B]) : Set[B]
Applies the given function f to each element of this set, then forms the union of all results.
Parameters
f - function to apply to each element.
Returns
a set containing all elements in each f(a0), ..., f(an) if this set contains a0, ..., an.
override def filter(p : (A) => Boolean) : Set[A]
Method filter removes all elements from the set for which the predicate p yields the value false.
Parameters
p - The predicate used to filter the set
Scala Library