The type implementing this traversable
A class supporting filtered operations. Instances of this class are returned by method withFilter
.
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.
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.
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
an empty set of type This
.
Creates an iterator over all the keys(or elements) contained in this collection greater than or equal to start
according to the ordering of this collection. x.keysIteratorFrom(y) is equivalent to but often more efficient than x.from(y).keysIterator.
The lower bound (inclusive) on the keys to be returned
Creates a ranged projection of this collection. Any mutations in the ranged projection will update this collection and vice versa.
Note: keys are not guaranteed to be consistent between this collection and the projection. This is the case for buffers where indexing is relative to the projection.
The lower-bound (inclusive) of the ranged projection. None
if there is no lower bound.
The upper-bound (exclusive) of the ranged projection. None
if there is no upper bound.
Test two objects for inequality.
true
if !(this == that), false otherwise.
Equivalent to x.hashCode
except for boxed numeric types and null
. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null
returns a hashcode where null.hashCode
throws a NullPointerException
.
a hash value consistent with ==
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.
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, omitting duplicates.
This method takes two or more elements to be added. Elements that already exist in the set will not be added. Another overloaded variant of this method handles the case where a single element is added.
Example:
scala> val a = Set(1, 3) + 2 + 3 a: scala.collection.immutable.Set[Int] = Set(1, 3, 2)
the first element to add.
the second element to add.
the remaining elements to add.
a new set with the given elements added, omitting duplicates.
Creates a new set by adding all elements contained in another collection to this set, omitting duplicates.
This method takes a collection of elements and adds all elements, omitting duplicates, into set.
Example:
scala> val a = Set(1, 2) ++ Set(2, "a") a: scala.collection.immutable.Set[Any] = Set(1, 2, a)
the collection containing the elements to add.
a new set with the given elements added, omitting duplicates.
Returns a new traversable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the traversable collection is the most specific superclass encompassing the element types of the two operands.
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 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
.
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 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
.
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.
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.
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.
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.
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.
The expression x == that
is equivalent to if (x eq null) that eq null else x.equals(that)
.
true
if the receiver object is equivalent to the argument; false
otherwise.
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. 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. 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.
This is a more general form of fold
and reduce
. It is similar to foldLeft
in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.
aggregate
splits the traversable or iterator into partitions and processes each partition by sequentially applying seqop
, starting with z
(like foldLeft
). Those intermediate results are then combined by using combop
(like fold
). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), so combop
may be invoked an arbitrary number of times (even 0).
As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First, seqop
transforms each input character to an Int and adds it to the sum (of the partition). Then, combop
just needs to sum up the intermediate results of the partitions:
List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
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.
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.
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
.
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.
ClassCastException
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.
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.
Create a copy of the receiver object.
The default implementation of the clone
method is platform dependent.
a copy of the receiver object.
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.
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)
Comparison function that orders keys.
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))
Copies the 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 target array is reached, or len
elements have been copied.
the array to fill.
the starting index.
the maximal number of elements to copy.
Copies the elements 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 target array is reached.
the array to fill.
Copies the elements 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 target array is reached.
the array to fill.
the starting index.
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.
the predicate used to test elements.
the number of elements satisfying the predicate p
.
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.
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. If n
is negative, don't drop any elements.
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.
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
.
Tests whether the argument (that
) is a reference to the receiver object (this
).
The eq
method implements an equivalence relation on non-null instances of AnyRef
, and has three additional properties:
x
and y
of type AnyRef
, multiple invocations of x.eq(y)
consistently returns true
or consistently returns false
.For any non-null instance x
of type AnyRef
, x.eq(null)
and null.eq(x)
returns false
.
null.eq(null)
returns true
. When overriding the equals
or hashCode
methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).
true
if the argument is a reference to the receiver object; false
otherwise.
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 at least one element of this iterable collection.
Note: may not terminate for infinite-sized collections.
the predicate used to test elements.
false
if this iterable collection is empty, otherwise true
if the given predicate p
holds for some of the elements of this iterable collection, otherwise false
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.
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.
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.
not specified by SLS as a member of AnyRef
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.
Returns the first key of the collection.
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.
Folds the elements of this traversable or iterator using the specified associative binary operator.
The order in which operations are performed on elements is unspecified and may be nondeterministic.
Note: will not terminate for infinite-sized collections.
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 the fold operator op
between all the elements and z
, or z
if this traversable or iterator is empty.
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. Returns z
if this traversable or iterator is empty.
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. Returns z
if this iterable collection is empty.
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 this iterable collection is empty or the given predicate p
holds for all elements of this iterable collection, otherwise false
.
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. Format strings are as for String.format
(@see java.lang.String.format).
Creates a ranged projection of this collection with no upper-bound.
The lower-bound (inclusive) of the ranged projection.
Returns the runtime class representation of the object.
a class object corresponding to the runtime type of the receiver.
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.
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. All strict collections are known to have finite size. For a non-strict collection such as Stream
, the predicate returns true
if all elements have been computed. It returns false
if the stream is not yet evaluated to the end. Non-empty Iterators usually return false
even if they were created from a collection with a known finite size.
Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize
returns true
. However, checking hasDefiniteSize
can provide an assurance that size is well-defined and non-termination is not a concern.
true
if this collection is known to have finite size, false
otherwise.
The hashCode method for reference types. See hashCode in scala.Any.
the hash code value for this object.
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.
NoSuchElementException
if the iterable collection is empty.
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.
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.
UnsupportedOperationException
if the traversable collection is empty.
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.
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.
true
if there is no element in the set, false
otherwise.
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 traversable collection can be repeatedly traversed.
true
Creates an iterator that contains all values from this collection greater than or equal to start
according to the ordering of this collection. x.iteratorFrom(y) is equivalent to but will usually be more efficient than x.from(y).iterator
The lower-bound (inclusive) of the iterator
return as a projection the set of keys in this collection
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.
NoSuchElementException
If the traversable collection is empty.
Returns the last key of the collection.
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.
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.
Finds the largest element.
the largest element of this set.
UnsupportedOperationException
if this set is empty.
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.
UnsupportedOperationException
if this set is empty.
Finds the smallest element.
the smallest element of this set
UnsupportedOperationException
if this set is empty.
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.
UnsupportedOperationException
if this set is empty.
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.
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.
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)"
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
. Overridden for mutable sets in `mutable.SetLike`.
Tests whether the traversable or iterator is not empty.
true
if the traversable or iterator contains at least one element, false
otherwise.
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.
not specified by SLS as a member of AnyRef
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.
a combiner for the parallel collection of type ParRepr
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.
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
.
Creates a ranged projection of this collection with both a lower-bound and an upper-bound.
The lower-bound (inclusive) of the ranged projection.
The upper-bound (exclusive) of the ranged projection.
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.
UnsupportedOperationException
if this traversable or iterator is empty.
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.
UnsupportedOperationException
if this traversable or iterator is empty.
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)
if this traversable or iterator is nonempty, None
otherwise.
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.
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.
UnsupportedOperationException
if this iterable collection is empty.
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)
if this traversable or iterator is nonempty, None
otherwise.
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.
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.
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.
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 the new element type B
.
collection with intermediate results
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 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 traversable or iterator.
Note: will not terminate for infinite-sized collections.
the number of elements in this traversable or iterator.
The size of this collection or iterator, if it can be cheaply computed
the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply
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.)
the number of elements per group
the distance between the first elements of successive groups
An iterator producing iterable collections of size size
, except the last element (which may be the only element) will be truncated if there are fewer than size
elements remaining to be grouped.
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
.) The "sliding window" step is set to one.
the number of elements per group
An iterator producing iterable collections of size size
, except the last element (which may be the only element) will be truncated if there are fewer than size
elements remaining to be grouped.
scala.collection.Iterator, method sliding
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. 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.
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.
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 of the given size. If the requested size is impossible, an empty iterator is returned.
the size of the subsets.
the iterator.
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.
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.
java.lang.UnsupportedOperationException
if the traversable collection is empty.
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.
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. If n
is negative, returns an empty iterable collection.
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.
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
. By default this is implemented as the current collection object itself, but this can be overridden.
Converts this set into another by copying all elements.
The collection type to build.
a new collection containing all elements of this set.
Create a range projection of this collection with no lower-bound.
The upper-bound (inclusive) of the ranged projection.
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.
a buffer containing all elements of this set.
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.
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.
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. 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.
Note: will not terminate for infinite-sized collections.
a list containing all elements of this traversable or iterator.
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. 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.
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.
a stream containing all elements of this iterable collection.
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 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.
Note: will not terminate for infinite-sized collections.
a vector containing all elements of this traversable or iterator.
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 ranged projection of this collection with no lower-bound.
The upper-bound (exclusive) of the ranged projection.
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.
a non-strict view of this iterable 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
.
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
.
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.
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.
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
.
(sortedSetLike: any2stringadd[SortedSetLike[A, This]]).+(other)
(sortedSetLike: MonadOps[A]).filter(p)
(sortedSetLike: MonadOps[A]).flatMap(f)
(sortedSetLike: MonadOps[A]).map(f)
(sortedSetLike: MonadOps[A]).withFilter(p)
© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/collection/SortedSetLike.html
A template for sets which are sorted.
2.8