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.
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.
Example:
scala> val a = List(1) a: List[Int] = List(1) scala> val b = List(2) b: List[Int] = List(2) scala> val c = a ++ b c: List[Int] = List(1, 2) scala> val d = List('a') d: List[Char] = List(a) scala> val e = c ++ d e: List[AnyVal] = List(1, 2, a)
the element type of the returned collection.
the traversable to append.
a new set 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.
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.
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 traversable collection followed by all elements of that
.
[use case] As with ++
, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
As with ++
, returns a new collection containing the elements from the left operand followed by the
elements from the right operand.
It differs from ++
in that the right operand determines the type of
the resulting collection rather than the left one.
Mnemonic: the COLon is on the side of the new COLlection type.
Example:
scala> val x = List(1) x: List[Int] = List(1) scala> val y = LinkedList(2) y: scala.collection.mutable.LinkedList[Int] = LinkedList(2) scala> val z = x ++: y z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
the element type of the returned collection.
the traversable to append.
a new set which contains all elements of this set
followed by all elements of that
.
Creates a new collection from this collection with some elements removed.
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.
the first element to remove.
the second element to remove.
the remaining elements to remove.
a new collection that contains all elements of the current collection except one less occurrence of each of the given elements.
Creates a new collection from this collection by removing all elements of another collection.
Creates a new collection from this collection by removing all elements of another collection.
the collection containing the removed elements.
a new collection that contains all elements of the current collection
except one less occurrence of each of the elements of elems
.
Applies a binary operator to a start value and all elements of this traversable or iterator, going left to right.
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.
the result type of the binary operator.
the start value.
the binary operator.
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 x_{1}, ..., x_{n}
are the elements of this traversable or iterator.
Applies a binary operator to all elements of this traversable or iterator and a start value, going right to left.
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
the result type of the binary operator.
the start value
the binary operator
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 x_{1}, ..., x_{n}
are the elements of this traversable or iterator.
Appends all elements of this traversable or iterator to a string builder.
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
the string builder to which elements are appended.
the string builder b
to which elements were appended.
Appends all elements of this traversable or iterator to a string builder using a separator string.
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
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 traversable or iterator to a string builder using start, end, and separator strings.
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)
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) and may be evaluated
more than once
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.
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 iterable collection should be compared
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.
[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 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.
Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.
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.
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)
The factory companion object that builds instances of class Set.
The factory companion object that builds instances of class Set.
(or its Iterable
superclass where class Set is not a Seq
.)
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.
[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.
[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 all elements of this traversable or iterator to a buffer.
Copies all elements of this traversable or iterator to a buffer.
Note: will not terminate for infinite-sized collections.
The buffer to which elements are copied.
Counts the number of elements in the traversable or iterator which satisfy a predicate.
Counts the number of elements in the traversable or iterator 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 iterable collection.
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.
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 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.
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 longest suffix of this traversable collection whose first element
does not satisfy the predicate p
.
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 iterable collection.
Tests whether a predicate holds for some of the elements of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true
if the given predicate p
holds for some of the
elements of this iterable collection, otherwise false
.
Selects all elements of this traversable collection which satisfy a predicate.
Selects all elements of this traversable collection which satisfy a predicate.
the predicate used to test elements.
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.
Selects all elements of this traversable collection which do not satisfy a predicate.
Selects all elements of this traversable collection which do not satisfy a predicate.
the predicate used to test elements.
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.
Finds the first element of the iterable collection satisfying a predicate, if any.
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.
the predicate used to test elements.
an option value containing the first element in the iterable collection
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:
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 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 function to apply to each element.
a new set resulting from applying the given collection-valued function
f
to each element of this set and concatenating the results.
[use case] Converts this set of traversable collections into a set formed by the elements of these traversable collections.
Converts this set of traversable collections into a set formed by the elements of these traversable collections.
The resulting collection's type will be guided by the static type of 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)
the type of the elements of each traversable collection.
a new set resulting from concatenating all element sets.
Folds the elements of this traversable or iterator using the specified associative binary operator.
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.
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 traversable or iterator, going left to right.
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.
the result type of the binary operator.
the start value.
the binary operator.
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 x_{1}, ..., x_{n}
are the elements of this traversable or iterator.
Applies a binary operator to all elements of this iterable collection and a start value, going right to left.
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.
the result type of the binary operator.
the start value.
the binary operator.
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 x_{1}, ..., x_{n}
are the elements of this iterable collection.
Tests whether a predicate holds for all elements of this iterable collection.
Tests whether a predicate holds for all elements of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
true
if the given predicate p
holds for all elements
of this iterable collection, otherwise false
.
[use case] 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 function that is applied for its side-effect to every element.
The result of function f
is discarded.
Returns string formatted according to given format
string.
Returns string formatted according to given format
string.
Format strings are as for String.format
(@see java.lang.String.format).
The generic builder that builds instances of CC at arbitrary element types.
The generic builder that builds instances of CC at arbitrary element types.
Partitions this traversable collection into a map of traversable collections according to some discriminator function.
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.
the type of keys returned by the discriminator function.
the discriminator function.
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
.
Partitions elements in fixed size iterable collections.
Partitions elements in fixed size iterable collections.
the number of elements per group
An iterator producing iterable collections of size size
, except the
last will be less than size size
if the elements don't divide evenly.
scala.collection.Iterator, method grouped
Tests whether this traversable collection is known to have a finite size.
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.
Note: many collection methods will not work on collections of infinite sizes.
true
if this collection is known to have finite size,
false
otherwise.
Selects the first element of this iterable collection.
Selects the first element of this iterable collection.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the first element of this iterable collection.
if the iterable collection 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 traversable collection 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 traversable collection consisting of all elements of this traversable collection except the last one.
if the traversable collection is empty.
Iterates over the inits of this traversable collection.
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
.
an iterator over all the inits of this traversable collection
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.
Tests whether this traversable collection can be repeatedly traversed.
Tests whether this traversable collection 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 traversable collection.
If the traversable collection 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 traversable collection$ 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 set resulting from applying the given function
f
to each element of this set and collecting the results.
[use case] Finds the largest element.
Finds the largest element.
the largest element of this set.
[use case] Finds the first element which yields the largest value measured by function f.
Finds the first element which yields the largest value measured by function f.
The result type of the function f.
The measuring function.
the first element of this set with the largest value measured by function f.
[use case] Finds the smallest element.
Finds the smallest element.
the smallest element of this set
[use case] Finds the first element which yields the smallest value measured by function f.
Finds the first element which yields the smallest value measured by function f.
The result type of the function f.
The measuring function.
the first element of this set with the smallest value measured by function f.
Displays all elements of this traversable or iterator in a string.
Displays all elements of this traversable or iterator in a string.
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.
Displays all elements of this traversable or iterator in a string using a separator string.
Displays all elements of this traversable or iterator in a string using a separator string.
the separator string.
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
.
List(1, 2, 3).mkString("|") = "1|2|3"
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
Displays all elements of this traversable or iterator in a string using start, end, and separator strings.
the starting string.
the separator string.
the ending string.
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
.
List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"
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 traversable or iterator is not empty.
Tests whether the traversable or iterator is not empty.
true
if the traversable or iterator contains at least one element, false
otherwise.
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 traversable collection in two traversable collections according to a predicate.
Partitions this traversable collection in two traversable collections according to a predicate.
the predicate on which to partition.
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.
[use case] Multiplies up the elements of this collection.
Multiplies up the elements of this collection.
the product of all elements in this 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 set and as result type of product
.
Examples of such types are: Long
, Float
, Double
, BigInt
.
Reduces the elements of this traversable or iterator using the specified associative binary operator.
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.
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 traversable or iterator is nonempty.
if this traversable or iterator is empty.
Applies a binary operator to all elements of this traversable or iterator, going left to right.
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.
the result type of the binary operator.
the binary operator.
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 x_{1}, ..., x_{n}
are the elements of this traversable or iterator.
if this traversable or iterator is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going left to right.
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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceLeft(op)
is this traversable or iterator is nonempty,
None
otherwise.
Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.
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.
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 iterable collection, going right to left.
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.
the result type of the binary operator.
the binary operator.
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 x_{1}, ..., x_{n}
are the elements of this iterable collection.
if this iterable collection is empty.
Optionally applies a binary operator to all elements of this traversable or iterator, going right to left.
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.
the result type of the binary operator.
the binary operator.
an option value containing the result of reduceRight(op)
is this traversable or iterator is nonempty,
None
otherwise.
The collection of type traversable collection underlying this TraversableLike
object.
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.
[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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
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 traversable collection containing the prefix scan of the elements in this traversable collection
Produces a collection containing cumulative results of applying the operator going left to right.
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.
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 cumulative results of applying the operator going right to left.
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)
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.
A version of this collection with all of the operations implemented sequentially (i.
A version of this collection with all of the operations implemented sequentially (i.e. in a single-threaded manner).
This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.
a sequential view of the collection.
The size of this traversable or iterator.
The size of this traversable or iterator.
Note: will not terminate for infinite-sized collections.
the number of elements in this traversable or iterator.
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.
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.
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
the distance between the first elements of successive groups (defaults to 1)
An iterator producing iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
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 iterable collections of size size
, except the
last and the only element will be truncated if there are
fewer elements than size.
scala.collection.Iterator, method sliding
Splits this traversable collection into a prefix/suffix pair according to a predicate.
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.
a pair consisting of the longest prefix of this traversable collection whose
elements all satisfy p
, and the rest of this traversable collection.
Splits this traversable collection into two at a given position.
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.
the position at which to split.
a pair of traversable collections consisting of the first n
elements of this traversable collection, 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 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 in this 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 set and as result type of sum
.
Examples of such types are: Long
, Float
, Double
, BigInt
.
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 traversable collection consisting of all elements of this traversable collection except the first one.
if the traversable collection is empty.
Iterates over the tails of this traversable collection.
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
.
an iterator over all the tails of this traversable collection
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.
the number of elements to take from this iterable collection.
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.
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 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.
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 longest prefix of this iterable collection whose elements all satisfy
the predicate p
.
The underlying collection seen as an instance of Iterable
.
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.
[use case] Converts this set into another by copying all elements.
Converts this set into another by copying all elements.
The collection type to build.
a new collection containing all elements of this set.
[use case] Converts this set to an array.
Converts this set to an array.
an array containing all elements of this set.
An ClassTag
must be available for the element type of this set.
Uses the contents of this set to create a new mutable buffer.
Uses the contents of this set to create a new mutable buffer.
a buffer containing all elements of this set.
A conversion from collections of type Repr
to Iterable
objects.
A conversion from collections of type Repr
to Iterable
objects.
By default this is implemented as just a cast, but this can be overridden.
Converts this traversable or iterator to an indexed sequence.
Converts this traversable or iterator to an indexed sequence.
Note: will not terminate for infinite-sized collections.
an indexed sequence containing all elements of this traversable or iterator.
Returns this iterable collection as an iterable collection.
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.
an Iterable
containing all elements of this iterable collection.
Returns an Iterator over the elements in this iterable collection.
Returns an Iterator over the elements in this iterable collection. Produces the same
result as iterator
.
Note: will not terminate for infinite-sized collections.
an Iterator containing all elements of this iterable collection.
Converts this traversable or iterator to a list.
Converts this traversable or iterator to a list.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this traversable or iterator.
[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 of type immutable.Map[T, U]
containing all key/value pairs of type (T, U)
of this set.
Converts this set to a sequence.
Converts this set to a sequence. As with toIterable
, it's lazy
in this default implementation, as this TraversableOnce
may be
lazy and unevaluated.
a sequence containing all elements of this set.
Converts this traversable or iterator to a set.
Converts this traversable or iterator to a set.
Note: will not terminate for infinite-sized collections.
a set containing all elements of this traversable or iterator.
Converts this iterable collection to a stream.
Converts this iterable collection to a stream.
Note: will not terminate for infinite-sized collections.
a stream containing all elements of this iterable collection.
Converts this set to a string.
Converts this set to a string.
a string representation of this collection. By default this
string consists of the stringPrefix
of this set, followed
by all elements separated by commas and enclosed in parentheses.
Converts this traversable collection to an unspecified Traversable.
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.
a Traversable containing all elements of this traversable collection.
Converts this traversable or iterator to a Vector.
Converts this traversable or iterator to a Vector.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this traversable or iterator.
Transposes this collection of traversable collections into a collection of collections.
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))
the type of the elements of each traversable collection.
an implicit conversion which asserts that the
element type of this collection is a Traversable
.
a two-dimensional collection of collections which has as nth row the nth column of this collection.
(Changed in version 2.9.0) transpose
throws an IllegalArgumentException
if collections are not uniformly sized.
if all collections in this collection are not of the same size.
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
.
Converts this collection of pairs into two collections of the first and second half of each pair.
Converts this collection of pairs into two collections of the first and second half of each pair.
val xs = CC( (1, "one"), (2, "two"), (3, "three")).unzip // xs == (CC(1, 2, 3), // CC(one, two, three))
the type of the first half of the element pairs
the type of the second half of the element pairs
an implicit conversion which asserts that the element type of this collection is a pair.
a pair of collections, containing the first, respectively second half of each element pair of this collection.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
Converts this collection of triples into three collections of the first, second, and third element of each triple.
val xs = CC( (1, "one", '1'), (2, "two", '2'), (3, "three", '3')).unzip3 // xs == (CC(1, 2, 3), // CC(one, two, three), // CC(1, 2, 3))
the type of the first member of the element triples
the type of the second member of the element triples
the type of the third member of the element triples
an implicit conversion which asserts that the element type of this collection is a triple.
a triple of collections, containing the first, second, respectively third member of each element triple of this collection.
Creates a non-strict view of a slice of this iterable collection.
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.
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 iterable collection, starting at index from
and extending up to (but not including) index until
.
Creates a non-strict view of this iterable collection.
Creates a non-strict view of this iterable collection.
a non-strict view of this iterable collection.
Creates a non-strict filter of this traversable collection.
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.
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 traversable collection
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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the second half of the returned pairs
The iterable providing the second half of each result pair
a new set 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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
the type of the second half of the returned pairs
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 set 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.
Note: might return different results for different runs, unless the underlying collection type is ordered.
A new set containing pairs consisting of all elements of this
set paired with their index. Indices start at 0
.
List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))
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
.
(set: any2stringadd[Set[A]]).+(other)
(set: MonadOps[A]).filter(p)
(set: MonadOps[A]).flatMap(f)
(set: MonadOps[A]).map(f)
(set: MonadOps[A]).withFilter(p)
A base trait for all sets, mutable as well as immutable.
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.Implementation note: If your additions and mutations return the same kind of set as the set you are defining, you should inherit from
SetLike
as well.1.0