The type implementing this traversable
The type implementing this traversable
A class supporting filtered operations.
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.
the element to be added
a new set that contains all elements of this set and that also
contains elem
.
Creates a new set with a given element removed from this set.
Creates a new set with a given element removed from this set.
the element to be removed
a new set that contains all elements of this set but that does not
contain elem
.
Tests if some element is contained in this set.
Tests if some element is contained in this set.
the element to test for membership.
true
if elem
is contained in this set, false
otherwise.
The empty set of the same type as this set
The empty set of the same type as this set
an empty set of type This
.
Test two objects for inequality.
Test two objects for inequality.
true
if !(this == that), false otherwise.
Equivalent to x.hashCode
except for boxed numeric types.
Equivalent to x.hashCode
except for boxed numeric types.
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.
a hash value consistent with ==
Computes the intersection between this set and another set.
Computes the intersection between this set and another set.
Note: Same as intersect
.
the set to intersect with.
a new set consisting of all elements that are both in this
set and in the given set that
.
The difference of this set and another set.
The difference of this set and another set.
Note: Same as diff
.
the set of elements to exclude.
a set containing those elements of this
set that are not also contained in the given set that
.
Creates a new set with additional elements.
Creates a new 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.
the first element to add.
the second element to add.
the remaining elements to add.
a new set with the given elements added.
Creates a new set by adding all elements contained in another collection to this set.
Creates a new set by adding all elements contained in another collection to this set.
the collection containing the added elements.
a new set with the given elements added.
[use case] Returns a new set containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new set containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the set is the most specific superclass encompassing the element types of the two operands (see example).
the element type of the returned collection.
the traversable to append.
a new collection of type That
which contains all elements
of this set followed by all elements of that
.
Returns a new set containing the elements from the left hand operand followed by the elements from the right hand operand.
Returns a new set containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the set is the most specific superclass encompassing the element types of the two operands (see example).
Example:
scala> val a = LinkedList(1) a: scala.collection.mutable.LinkedList[Int] = LinkedList(1) scala> val b = LinkedList(2) b: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val c = a ++ b c: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2) scala> val d = LinkedList('a') d: scala.collection.mutable.LinkedList[Char] = LinkedList(a) scala> val e = c ++ d e: scala.collection.mutable.LinkedList[AnyVal] = LinkedList(1, 2, a)
the element type of the returned collection.
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.
the traversable to append.
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
.
a new collection of type That
which contains all elements
of this set followed by all elements of 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.
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.
the element type of the returned collection.
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.
the traversable to append.
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
.
a new set which contains all elements of this set
followed by all elements of that
.
[use case] Concatenates this set with the elements of a traversable collection.
Concatenates this set with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.
the element type of the returned collection.
the traversable to append.
a new collection of type That
which contains all elements
of this set followed by all elements of that
.
Concatenates this set with the elements of a traversable collection.
Concatenates this set with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.
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)
the element type of the returned collection.
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.
the traversable to append.
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
.
a new collection of type That
which contains all elements
of this set followed by all elements of that
.
Creates a new set from this set with some elements removed.
Creates a new set from this 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.
the first element to remove.
the second element to remove.
the remaining elements to remove.
a new set that contains all elements of the current set except one less occurrence of each of the given elements.
Creates a new set from this set by removing all elements of another collection.
Creates a new set from this set by removing all elements of another collection.
a new set that contains all elements of the current set
except one less occurrence of each of the elements of elems
.
Applies a binary operator to a start value and all elements of this set, going left to right.
Applies a binary operator to a start value and all elements of this 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this set,
going left to right with the start value z
on the left:
op(...op(op(z, x1), x2), ..., xn)
where x_{1}, ..., x_{n}
are the elements of this set.
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
Applies a binary operator to all elements of this set and a start value, going right to left.
Applies a binary operator to all elements of this 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
the result type of the binary operator.
the start value
the binary operator
the result of inserting op
between consecutive elements of this set,
going right to left with the start value z
on the right:
op(x1, op(x2, ... op(xn, z)...))
where x_{1}, ..., x_{n}
are the elements of this set.
Test two objects for equality.
Test two objects for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
Appends all elements of this set to a string builder.
Appends all elements of this set to a string builder.
The written text consists of the string representations (w.r.t. the method
toString
) of all elements of this 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
the string builder to which elements are appended.
the string builder b
to which elements were appended.
Appends all elements of this set to a string builder using a separator string.
Appends all elements of this 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 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
the string builder to which elements are appended.
the separator string.
the string builder b
to which elements were appended.
Appends all elements of this set to a string builder using start, end, and separator strings.
Appends all elements of this 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 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)
the string builder to which elements are appended.
the starting string.
the separator string.
the ending string.
the string builder b
to which elements were appended.
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).
the type of accumulated results
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)
an operator used to accumulate results within a partition
an associative operator used to combine results from different partitions
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.
the result type of function g
a function R => A
a new function f
such that f(x) == g(apply(x))
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.
the element to test for membership.
true
if elem
is contained in this set, false
otherwise.
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.
the receiver object.
if the receiver object is not an instance of the erasure of type T0
.
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.
The object with which this set should be compared
true
, if this set can possibly equal that
, false
otherwise. The test
takes into consideration only the run-time types of objects but ignores their elements.
Create a copy of the receiver object.
[use case] Builds a new collection by applying a partial function to all elements of this set on which the function is defined.
Builds a new collection by applying a partial function to all elements of this set on which the function is defined.
the element type of the returned collection.
the partial function which filters and maps the set.
a new collection of type That
resulting from applying the partial function
pf
to each element on which it is defined and collecting the results.
The order of the elements is preserved.
Builds a new collection by applying a partial function to all elements of this set on which the function is defined.
Builds a new collection by applying a partial function to all elements of this set on which the function is defined.
the element type of the returned collection.
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.
the partial function which filters and maps the set.
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
.
a new collection of type That
resulting from applying the partial function
pf
to each element on which it is defined and collecting the results.
The order of the elements is preserved.
Finds the first element of the set for which the given partial function is defined, and applies the partial function to it.
Finds the first element of the 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.
the partial function
an option value containing pf applied to the first
value for which it is defined, or None
if none exists.
Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)
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.
the type to which function g
can be applied
a function A => T1
a new function f
such that f(x) == apply(g(x))
[use case] Copies elements of this set to an array.
Copies elements of this set to an array.
Fills the given array xs
with at most len
elements of
this set, starting at position start
.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached, or len
elements have been copied.
the array to fill.
the starting index.
the maximal number of elements to copy.
Copies elements of this set to an array.
Copies elements of this set to an array.
Fills the given array xs
with at most len
elements of
this set, starting at position start
.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached, or len
elements have been copied.
the type of the elements of the array.
the array to fill.
the starting index.
the maximal number of elements to copy.
[use case] Copies values of this set to an array.
Copies values of this set to an array.
Fills the given array xs
with values of this set.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached.
the array to fill.
Copies values of this set to an array.
Copies values of this set to an array.
Fills the given array xs
with values of this set.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached.
the type of the elements of the array.
the array to fill.
[use case] Copies values of this set to an array.
Copies values of this set to an array.
Fills the given array xs
with values of this set, beginning at index start
.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached.
the array to fill.
the starting index.
Copies values of this set to an array.
Copies values of this set to an array.
Fills the given array xs
with values of this set, beginning at index start
.
Copying will stop once either the end of the current set is reached,
or the end of the array is reached.
the type of the elements of the array.
the array to fill.
the starting index.
Copies all elements of this set to a buffer.
Copies all elements of this set to a buffer.
The buffer to which elements are copied.
Counts the number of elements in the set which satisfy a predicate.
Counts the number of elements in the set which satisfy a predicate.
the predicate used to test elements.
the number of elements satisfying the predicate p
.
Computes the difference of this set and another set.
Computes the difference of this set and another set.
the set of elements to exclude.
a set containing those elements of this
set that are not also contained in the given set that
.
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.
the number of elements to drop from this set.
a set consisting of all elements of this set except the first n
ones, or else the
empty set, if this set has less than n
elements.
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.
The number of elements to take
a set consisting of all elements of this set except the last n
ones, or else the
empty set, if this set has less than n
elements.
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.
The predicate used to test elements.
the longest suffix of this set whose first element
does not satisfy the predicate p
.
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:
x
and y
of type AnyRef
, multiple invocations of
x.eq(y)
consistently returns true
or consistently returns false
.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
).
true
if the argument is a reference to the receiver object; false
otherwise.
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.
the other object
true
if that
is a set which contains the same elements
as this set.
Tests whether a predicate holds for some of the elements of this set.
Tests whether a predicate holds for some of the elements of this set.
the predicate used to test elements.
true
if the given predicate p
holds for some of the
elements of this set, otherwise false
.
Selects all elements of this set which satisfy a predicate.
Selects all elements of this set which satisfy a predicate.
the predicate used to test elements.
a new set consisting of all elements of this set that satisfy the given
predicate p
. The order of the elements is preserved.
Selects all elements of this set which do not satisfy a predicate.
Selects all elements of this set which do not satisfy a predicate.
the predicate used to test elements.
a new set consisting of all elements of this set that do not satisfy the given
predicate p
. The order of the elements is preserved.
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.
Finds the first element of the set satisfying a predicate, if any.
Finds the first element of the set satisfying a predicate, if any.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the predicate used to test elements.
an option value containing the first element in the set
that satisfies p
, or None
if none exists.
[use case] Builds a new collection by applying a function to all elements of this set and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this set and using the elements of the resulting collections. For example:
the element type of the returned collection.
the function to apply to each element.
a new collection of type That
resulting from applying the given collection-valued function
f
to each element of this set and concatenating the results.
Builds a new collection by applying a function to all elements of this set and using the elements of the resulting collections.
Builds a new collection by applying a function to all elements of this 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 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 a 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)
the element type of the returned collection.
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.
the function to apply to each element.
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
.
a new collection of type That
resulting from applying the given collection-valued function
f
to each element of this set and concatenating the results.
Folds the elements of this set using the specified associative binary operator.
Folds the elements of this set using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
a type parameter for the binary operator, a supertype of A
.
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.)
a binary operator that must be associative
the result of applying fold operator op
between all the elements and z
Applies a binary operator to a start value and all elements of this set, going left to right.
Applies a binary operator to a start value and all elements of this 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this set,
going left to right with the start value z
on the left:
op(...op(z, x1), x2, ..., xn)
where x_{1}, ..., x_{n}
are the elements of this set.
Applies a binary operator to all elements of this set and a start value, going right to left.
Applies a binary operator to all elements of this 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.
the result type of the binary operator.
the start value.
the binary operator.
the result of inserting op
between consecutive elements of this set,
going right to left with the start value z
on the right:
op(x1, op(x2, ... op(xn, z)...))
where x_{1}, ..., x_{n}
are the elements of this set.
Tests whether a predicate holds for all elements of this set.
Tests whether a predicate holds for all elements of this set.
the predicate used to test elements.
true
if the given predicate p
holds for all elements
of this set, otherwise false
.
[use case] Applies a function f
to all elements of this set.
Applies a function f
to all elements of this set.
the function that is applied for its side-effect to every element.
The result of function f
is discarded.
Applies a function f
to all elements of this set.
Applies a function f
to all elements of this set.
Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.
the type parameter describing the result of function f
.
This result will always be ignored. Typically U
is Unit
,
but this is not necessary.
the function that is applied for its side-effect to every element.
The result of function f
is discarded.
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.
a representation that corresponds to the dynamic class of the receiver object.
not specified by SLS as a member of AnyRef
Partitions this set into a map of sets according to some discriminator function.
Partitions this set into a map of 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 set.
the type of keys returned by the discriminator function.
the discriminator function.
A map from keys to 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 set of those elements x
for which f(x)
equals k
.
Partitions elements in fixed size sets.
Partitions elements in fixed size sets.
the number of elements per group
An iterator producing sets of size size
, except the
last will be truncated if the elements don't divide evenly.
Iterator#grouped
Tests whether this set is known to have a finite size.
Tests whether this 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.
true
if this collection is known to have finite size, false
otherwise.
The hashCode method for reference types.
The hashCode method for reference types. See hashCode in Any.
the hash code value for this object.
Selects the first element of this set.
Selects the first element of this set.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this set.
if the set is empty.
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.
the first element of this set if it is nonempty, None
if it is empty.
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.
a set consisting of all elements of this set except the last one.
if the set is empty.
Iterates over the inits of this set.
Iterates over the inits of this set. The first value will be this
set and the final one will be an empty set, with the intervening
values the results of successive applications of init
.
an iterator over all the inits of this set
List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)
Computes the intersection between this set and another set.
Computes the intersection between this set and another set.
the set to intersect with.
a new set consisting of all elements that are both in this
set and in the given set that
.
Tests if this set is empty.
Tests if this set is empty.
true
if there is no element in the set, false
otherwise.
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.
true
if the receiver object is an instance of erasure of type T0
; false
otherwise.
Tests whether this set can be repeatedly traversed.
Tests whether this set can be repeatedly traversed.
true
Selects the last element.
Selects the last element.
Note: might return different results for different runs, unless the underlying collection type is ordered.
The last element of this set.
If the set is empty.
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.
the last element of this set$ if it is nonempty, None
if it is empty.
[use case] Builds a new collection by applying a function to all elements of this set.
Builds a new collection by applying a function to all elements of this set.
the element type of the returned collection.
the function to apply to each element.
a new collection of type That
resulting from applying the given function
f
to each element of this set and collecting the results.
Builds a new collection by applying a function to all elements of this set.
Builds a new collection by applying a function to all elements of this set.
the element type of the returned collection.
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.
the function to apply to each element.
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
.
a new collection of type That
resulting from applying the given function
f
to each element of this set and collecting the results.
(Changed in version 2.8.0) Set.map now returns a Set, so it will discard duplicate values.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this set with respect to the ordering cmp
.
Finds the largest element.
Finds the largest element.
The type over which the ordering is defined.
An ordering to be used for comparing elements.
the largest element of this set with respect to the ordering cmp
.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this set with respect to the ordering cmp
.
Finds the smallest element.
Finds the smallest element.
The type over which the ordering is defined.
An ordering to be used for comparing elements.
the smallest element of this set with respect to the ordering cmp
.
Displays all elements of this set in a string.
Displays all elements of this set in a string.
a string representation of this set. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this set follow each other without any
separator string.
Displays all elements of this set in a string using a separator string.
Displays all elements of this set in a string using a separator string.
the separator string.
a string representation of this set. In the resulting string
the string representations (w.r.t. the method toString
)
of all elements of this set are separated by the string sep
.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this set in a string using start, end, and separator strings.
Displays all elements of this set in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
a string representation of this 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 set are separated by
the string sep
.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
Equivalent to !(this eq that)
.
Equivalent to !(this eq that)
.
true
if the argument is not a reference to the receiver object; false
otherwise.
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
.
Tests whether the set is not empty.
Tests whether the set is not empty.
true
if the set contains at least one element, false
otherwise.
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.
not specified by SLS as a member of AnyRef
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.
not specified by SLS as a member of AnyRef
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.
a parallel implementation of this collection
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.
a combiner for the parallel collection of type ParRepr
Partitions this set in two sets according to a predicate.
Partitions this set in two sets according to a predicate.
the predicate on which to partition.
a pair of sets: the first set consists of all elements that
satisfy the predicate p
and the second set consists of all elements
that don't. The relative order of the elements in the resulting sets
is the same as in the original set.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements of this set with respect to the *
operator in num
.
Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the result type of the *
operator.
an implicit parameter defining a set of numeric operations
which includes the *
operator to be used in forming the product.
the product of all elements of this set with respect to the *
operator in num
.
Reduces the elements of this set using the specified associative binary operator.
Reduces the elements of this set using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A
.
A binary operator that must be associative.
The result of applying reduce operator op
between all the elements if the set is nonempty.
if this set is empty.
Optionally applies a binary operator to all elements of this set, going left to right.
Optionally applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op)
is this set is nonempty,
None
otherwise.
Reduces the elements of this set, if any, using the specified associative binary operator.
Reduces the elements of this set, if any, using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
A type parameter for the binary operator, a supertype of A
.
A binary operator that must be associative.
An option value containing result of applying reduce operator op
between all
the elements if the collection is nonempty, and None
otherwise.
Applies a binary operator to all elements of this set, going right to left.
Applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
the result of inserting op
between consecutive elements of this set,
going right to left:
op(x,,1,,, op(x,,2,,, ..., op(x,,n-1,,, x,,n,,)...))
where x_{1}, ..., x_{n}
are the elements of this set.
if this set is empty.
Optionally applies a binary operator to all elements of this set, going right to left.
Optionally applies a binary operator to all elements of this 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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op)
is this set is nonempty,
None
otherwise.
The collection of type set underlying this TraversableLike
object.
The collection of type set underlying this TraversableLike
object.
By default this is implemented as the TraversableLike
object itself,
but this can be overridden.
[use case] Checks if the other iterable collection contains the same elements in the same order as this set.
Checks if the other iterable collection contains the same elements in the same order as this set.
the collection to compare with.
true
, if both collections contain the same elements in the same order, false
otherwise.
Checks if the other iterable collection contains the same elements in the same order as this set.
Checks if the other iterable collection contains the same elements in the same order as this set.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the elements of collection that
.
the collection to compare with.
true
, if both collections contain the same elements in the same order, false
otherwise.
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.
element type of the resulting collection
type of the resulting collection
neutral element for the operator op
the associative operator for the scan
combiner factory which provides a combiner
a new set containing the prefix scan of the elements in this set
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.
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
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
.
collection with intermediate results
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)
the type of the elements in the resulting collection
the actual type of the resulting collection
the initial value
the binary operator applied to the intermediate result and the element
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
.
collection with intermediate results
(Changed in version 2.9.0) The behavior of scanRight
has changed. The previous behavior can be reproduced with scanRight.reverse.
The size of this set.
The size of this set.
the number of elements in this set.
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.
the lowest index to include from this set.
the highest index to EXCLUDE from this set.
a set containing the elements greater than or equal to
index from
extending up to (but not including) index until
of this set.
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.)
the number of elements per group
An iterator producing sets of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
Iterator#sliding
Splits this set into a prefix/suffix pair according to a predicate.
Splits this 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.
the test predicate
a pair consisting of the longest prefix of this set whose
elements all satisfy p
, and the rest of this set.
Splits this set into two at a given position.
Splits this 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.
the position at which to split.
a pair of sets consisting of the first n
elements of this set, and the other elements.
Defines the prefix of this object's toString
representation.
Defines the prefix of this object's toString
representation.
a string representation which starts the result of toString
applied to this set.
Unless overridden this is simply "Set"
.
Tests whether this set is a subset of another set.
Tests whether this set is a subset of another set.
the set to test.
true
if this set is a subset of that
, i.e. if
every element of this set is also an element of that
.
An iterator over all subsets of this set.
An iterator over all subsets of this set.
the iterator.
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.
the size of the subsets.
the iterator.
[use case] Sums up the elements of this collection.
Sums up the elements of this collection.
the sum of all elements of this set with respect to the +
operator in num
.
Sums up the elements of this collection.
Sums up the elements of this collection.
the result type of the +
operator.
an implicit parameter defining a set of numeric operations
which includes the +
operator to be used in forming the sum.
the sum of all elements of this set with respect to the +
operator in num
.
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.
a set consisting of all elements of this set except the first one.
if the set is empty.
Iterates over the tails of this set.
Iterates over the tails of this set. The first value will be this
set and the final one will be an empty set, with the intervening
values the results of successive applications of tail
.
an iterator over all the tails of this set
List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)
Selects first n elements.
Selects first n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
Tt number of elements to take from this set.
a set consisting only of the first n
elements of this set,
or else the whole set, if it has less than n
elements.
Selects last n elements.
Selects last n elements.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the number of elements to take
a set consisting only of the last n
elements of this set, or else the
whole set, if it has less than n
elements.
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.
The predicate used to test elements.
the longest prefix of this set whose elements all satisfy
the predicate p
.
The underlying collection seen as an instance of Set
.
The underlying collection seen as an instance of Set
.
By default this is implemented as the current collection object itself,
but this can be overridden.
[use case] Converts this set to an array.
Converts this set to an array.
an array containing all elements of this set.
Converts this set to an array.
Converts this set to an array.
the type of the elements of the array. A ClassManifest
for
this type must be available.
an array containing all elements of this set.
Converts this set to a mutable buffer.
Converts this set to a mutable buffer.
a buffer containing all elements of this set.
A conversion from collections of type Repr
to Set
objects.
A conversion from collections of type Repr
to Set
objects.
By default this is implemented as just a cast, but this can be overridden.
Converts this set to an indexed sequence.
Converts this set to an indexed sequence.
an indexed sequence containing all elements of this set.
Converts this set to an iterable collection.
Converts this 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).
an Iterable
containing all elements of this set.
Returns an Iterator over the elements in this set.
Returns an Iterator over the elements in this set. Will return the same Iterator if this instance is already an Iterator.
an Iterator containing all elements of this set.
Converts this set to a list.
Converts this set to a list.
a list containing all elements of this set.
[use case] Converts this set to a map.
Converts this 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.
a map containing all elements of this set.
Converts this set to a map.
Converts this 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.
a map containing all elements of this set.
Overridden for efficiency.
Overridden for efficiency.
a sequence containing all elements of this set.
Converts this set to a set.
Converts this set to a set.
a set containing all elements of this set.
Converts this set to a stream.
Converts this set to a stream.
a stream containing all elements of this set.
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.
a String representation of the object.
Converts this set to an unspecified Traversable.
Converts this set to an unspecified Traversable. Will return the same collection if this instance is already Traversable.
a Traversable containing all elements of this set.
Computes the union between of set and another set.
Computes the union between of set and another set.
the set to form the union with.
a new set consisting of all elements that are in this
set or in the given set that
.
Creates a non-strict view of a slice of this set.
Creates a non-strict view of a slice of this set.
Note: the difference between view
and slice
is that view
produces
a view of the current set, whereas slice
produces a new 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.
the index of the first element of the view
the index of the element following the view
a non-strict view of a slice of this set, starting at index from
and extending up to (but not including) index until
.
Creates a non-strict view of this set.
Creates a non-strict view of this set.
a non-strict view of this set.
Creates a non-strict filter of this set.
Creates a non-strict filter of this 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.
the predicate used to test elements.
an object of class WithFilter
, which supports
map
, flatMap
, foreach
, and withFilter
operations.
All these operations apply to those elements of this set which
satisfy the predicate p
.
[use case] Returns a set formed from this set and another iterable collection by combining corresponding elements in pairs.
Returns a set formed from this 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.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new collection of type That
containing pairs consisting of
corresponding elements of this set and that
. The length
of the returned collection is the minimum of the lengths of this set and that
.
Returns a set formed from this set and another iterable collection by combining corresponding elements in pairs.
Returns a set formed from this 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.
the type of the first half of the returned pairs (this is always a supertype
of the collection's element type A
).
the type of the second half of the returned pairs
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 (A1, B)
being admissible for that class,
which means that an implicit instance of type CanBuildFrom[Repr, (A1, B), That]
.
is found.
The iterable providing the second half of each result pair
an implicit value of class CanBuildFrom
which determines the
result class That
from the current representation type Repr
and the new element type (A1, B)
.
a new collection of type That
containing pairs consisting of
corresponding elements of this set and that
. The length
of the returned collection is the minimum of the lengths of this set and that
.
[use case] Returns a set formed from this set and another iterable collection by combining corresponding elements in pairs.
Returns a set formed from this 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.
the iterable providing the second half of each result pair
the element to be used to fill up the result if this set is shorter than that
.
the element to be used to fill up the result if that
is shorter than this set.
a new collection of type That
containing pairs consisting of
corresponding elements of this set and that
. The length
of the returned collection is the maximum of the lengths of this set and that
.
If this set is shorter than that
, thisElem
values are used to pad the result.
If that
is shorter than this set, thatElem
values are used to pad the result.
Returns a set formed from this set and another iterable collection by combining corresponding elements in pairs.
Returns a set formed from this 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.
the iterable providing the second half of each result pair
the element to be used to fill up the result if this set is shorter than that
.
the element to be used to fill up the result if that
is shorter than this set.
a new collection of type That
containing pairs consisting of
corresponding elements of this set and that
. The length
of the returned collection is the maximum of the lengths of this set and that
.
If this set is shorter than that
, thisElem
values are used to pad the result.
If that
is shorter than this set, thatElem
values are used to pad the result.
[use case] Zips this set with its indices.
Zips this set with its indices.
A new collection of type That
containing pairs consisting of all elements of this
set paired with their index. Indices start at 0
.
Zips this set with its indices.
Zips this set with its indices.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the first half of the returned pairs (this is always a supertype
of the collection's element type A
).
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 (A1, Int)
being admissible for that class,
which means that an implicit instance of type CanBuildFrom[Repr, (A1, Int), That]
.
is found.
A new collection of type That
containing pairs consisting of all elements of this
set paired with their index. Indices start at 0
.
Computes the union between this set and another set.
Computes the union between this set and another set.
Note: Same as union
.
the set to form the union with.
a new set consisting of all elements that are in this
set or in the given set that
.
This method is an alias for intersect
.
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
.
the set to intersect with
(Since version 2.8.0) use & instead
(Since version 2.8.0) use iterator' instead
(Since version 2.8.0) use head' instead
None
if iterable is empty.
None
if iterable is empty.
(Since version 2.8.0) use headOption' instead
returns a projection that can be used to call non-strict filter
,
map
, and flatMap
methods that build projections
of the collection.
returns a projection that can be used to call non-strict filter
,
map
, and flatMap
methods that build projections
of the collection.
(Since version 2.8.0) use view' instead
A template trait for sets.
A set is a collection that contains no duplicate elements.
Implementation note: This trait provides most of the operations of a
Set
independently of its representation. It is typically inherited by concrete implementations of sets.To implement a concrete set, you need to provide implementations of the following methods:
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
andsize
for efficiency.2.8