Scala 3/scala/scala.collection/IterableOnce

IterableOnce

scala.collection.IterableOnce

See theIterableOnce companion object

A template trait for collections which can be traversed either once only or one or more times.

Note: IterableOnce does not extend IterableOnceOps. This is different than the general design of the collections library, which uses the following pattern:

trait Seq extends Iterable with SeqOps
trait SeqOps extends IterableOps

trait IndexedSeq extends Seq with IndexedSeqOps
trait IndexedSeqOps extends SeqOps

The goal is to provide a minimal interface without any sequential operations. This allows third-party extension like Scala parallel collections to integrate at the level of IterableOnce without inheriting unwanted implementations.

Attributes

Companion: object
Source: IterableOnce.scala
Graph
Supertypes: class Any
Known subtypes: trait Iterable[A]

trait Iterable[A]

trait Map[K, V]

class AbstractMap[K, V]

class HashMap[K, V]

class IntMap[T]

class ListMap[K, V]

class LongMap[T]

class Map1[K, V]

class Map2[K, V]

class Map3[K, V]

class Map4[K, V]

class WithDefault[K, V]

class WithDefault[K, V]

class TreeMap[K, V]

class TreeSeqMap[K, V]

class VectorMap[K, V]

trait SeqMap[K, V]

trait SortedMap[K, V]

trait Seq[A]

class AbstractSeq[A]

class ArraySeq[A]

class ofBoolean

class ofByte

class ofChar

class ofDouble

class ofFloat

class ofInt

class ofLong

class ofRef[T]

class ofShort

class ofUnit

class LazyList[A]

class List[A]

class ::[A]

object Nil

class NumericRange[T]

class Exclusive[T]

class Inclusive[T]

class Queue[A]

class Range

class Exclusive

class Inclusive

class Stream[A]

class Cons[A]

object Empty

class Vector[A]

class WrappedString

trait IndexedSeq[A]

trait LinearSeq[A]

trait Set[A]

class AbstractSet[A]

class BitSet

class BitSet1

class BitSet2

class BitSetN

class HashSet[A]

class ListSet[A]

class Set1[A]

class Set2[A]

class Set3[A]

class Set4[A]

class SortedMapOps.this.ImmutableKeySortedSet

class TreeSet[A]

class Enumeration.this.ValueSet

trait SortedSet[A]

trait Iterable[A]

class AbstractIterable[A]

class PriorityQueue[A]

trait Map[K, V]

trait Map[K, V]

class TrieMap[K, V]

class AbstractMap[K, V]

class AnyRefMap[K, V]

class CollisionProofHashMap[K, V]

class HashMap[K, V]

class LinkedHashMap[K, V]

class ListMap[K, V]

class LongMap[V]

class WithDefault[K, V]

class WithDefault[K, V]

class OpenHashMap[Key, Value]

class TreeMap[K, V]

class SystemProperties

trait MultiMap[K, V]

trait SeqMap[K, V]

trait SortedMap[K, V]

trait Seq[A]

class AbstractSeq[A]

class AbstractBuffer[A]

class ArrayBuffer[A]

class ArrayDeque[A]

class Queue[A]

class Stack[A]

class ListBuffer[A]

class UnrolledBuffer[T]

class ArraySeq[T]

class ofBoolean

class ofByte

class ofChar

class ofDouble

class ofFloat

class ofInt

class ofLong

class ofRef[T]

class ofShort

class ofUnit

class StringBuilder

trait Buffer[A]

trait IndexedBuffer[A]

trait IndexedSeq[T]

class Accumulator[A, CC, C]

class AnyAccumulator[A]

class DoubleAccumulator

class IntAccumulator

class LongAccumulator

trait Set[A]

class AbstractSet[A]

class BitSet

class HashSet[A]

class LinkedHashSet[A]

class TreeSet[A]

trait SortedSet[A]

class AbstractIterable[A]

class AbstractMap[K, V]

class AbstractSeq[A]

class AbstractSet[A]

class AbstractView[A]

class AbstractMapView[K, V]

class Filter[K, V]

class FilterKeys[K, V]

class Id[K, V]

class MapValues[K, V, W]

class TapEach[K, V, U]

class AbstractSeqView[A]

class AbstractIndexedSeqView[A]

class ArrayBufferView[A]

class Slice[A]

class StringView

class Id[A]

class Id[A]

class Reverse[A]

class Reverse[A]

class Appended[A]

class Appended[A]

class Appended[A]

class Collect[A, B]

class Concat[A]

class Concat[A]

class Concat[A]

class DistinctBy[A, B]

class Drop[A]

class Drop[A]

class Drop[A]

class DropRight[A]

class DropRight[A]

class DropRight[A]

class DropWhile[A]

class Elems[A]

object Empty

class Fill[A]

class Filter[A]

class FlatMap[A, B]

class Iterate[A]

class LeftPartitionMapped[A, A1, A2]

class Map[A, B]

class Map[A, B]

class Map[A, B]

class PadTo[A]

class Prepended[A]

class Prepended[A]

class Prepended[A]

class RightPartitionMapped[A, A1, A2]

class ScanLeft[A, B]

class Single[A]

class Tabulate[A]

class Take[A]

class Take[A]

class Take[A]

class TakeRight[A]

class TakeRight[A]

class TakeRight[A]

class TakeWhile[A]

class Unfold[A, S]

class Updated[A]

class Zip[A, B]

class ZipAll[A, B]

class ZipWithIndex[A]

trait Map[K, V]

trait DefaultMap[K, V]

trait SeqMap[K, V]

trait SortedMap[K, V]

trait Seq[A]

trait IndexedSeq[A]

trait LinearSeq[A]

trait Set[A]

trait SortedSet[A]

trait BitSet

trait View[A]

trait MapView[K, V]

trait SeqView[A]

trait IndexedSeqView[A]

class Sorted[A, B]

trait IterableOps[A, CC, C]

trait MapOps[K, V, CC, C]

trait SortedMapOps[K, V, CC, C]

trait StrictOptimizedSortedMapOps[K, V, CC, C]

trait StrictOptimizedMapOps[K, V, CC, C]

trait MapOps[K, V, CC, C]

trait SortedMapOps[K, V, CC, C]

trait SetOps[A, CC, C]

trait SortedSetOps[A, CC, C]

trait EvidenceIterableFactoryDefaults[A, CC, Ev]

trait IterableFactoryDefaults[A, CC]

trait MapFactoryDefaults[K, V, CC, WithFilterCC]

class WeakHashMap[K, V]

trait MapOps[K, V, CC, C]

trait SortedMapFactoryDefaults[K, V, CC, WithFilterCC, UnsortedCC]

trait SortedMapOps[K, V, CC, C]

trait StrictOptimizedSortedMapOps[K, V, CC, C]

trait StrictOptimizedMapOps[K, V, CC, C]

trait SeqOps[A, CC, C]

trait SeqOps[A, CC, C]

trait IndexedSeqOps[A, CC, C]

trait LinearSeqOps[A, CC, C]

trait StrictOptimizedSeqOps[A, CC, C]

trait SeqOps[A, CC, C]

trait IndexedSeqOps[A, CC, C]

trait IndexedSeqOps[A, CC, C]

trait LinearSeqOps[A, CC, C]

trait StrictOptimizedLinearSeqOps[A, CC, C]

trait StrictOptimizedSeqOps[A, CC, C]

trait ArrayDequeOps[A, CC, C]

trait SetOps[A, CC, C]

trait SetOps[A, CC, C]

trait SortedSetOps[A, CC, C]

trait StrictOptimizedSortedSetOps[A, CC, C]

trait StrictOptimizedSetOps[A, CC, C]

trait SortedSetOps[A, CC, C]

trait BitSetOps[C]

trait SortedSetFactoryDefaults[A, CC, WithFilterCC]

trait StrictOptimizedSortedSetOps[A, CC, C]

trait StrictOptimizedSetOps[A, CC, C]

trait StrictOptimizedIterableOps[A, CC, C]

trait Iterator[A]

class AbstractIterator[A]

class Iterator.this.GroupedIterator[B]

class BufferedSource.this.BufferedLineIterator

class Source.this.LineIterator

class MatchIterator

trait BufferedIterator[A]

class Source

class BufferedSource

class Option[A]

object None

class Some[A]
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Members list

Value members

Abstract methods

def iterator: Iterator[A]

An scala.collection.Iterator over the elements of this collection.

If an IterableOnce object is in fact an scala.collection.Iterator, this method always returns itself, in its current state, but if it is an scala.collection.Iterable, this method always returns a new scala.collection.Iterator.

Attributes

Source: IterableOnce.scala

Concrete methods

def knownSize: Int

The number of elements in this collection, if it can be cheaply computed, -1 otherwise.

The number of elements in this collection, if it can be cheaply computed, -1 otherwise. Cheaply usually means: Not requiring a collection traversal.

Attributes

Source: IterableOnce.scala

def stepper[S <: Stepper[_]](implicit shape: StepperShape[A, S]): S

Returns a scala.collection.Stepper for the elements of this collection.

The Stepper enables creating a Java stream to operate on the collection, see scala.jdk.StreamConverters. For collections holding primitive values, the Stepper can be used as an iterator which doesn't box the elements.

The implicit scala.collection.StepperShape parameter defines the resulting Stepper type according to the element type of this collection.

For collections of Int, Short, Byte or Char, an scala.collection.IntStepper is returned
For collections of Double or Float, a scala.collection.DoubleStepper is returned
For collections of Long a scala.collection.LongStepper is returned
For any other element type, an scala.collection.AnyStepper is returned

Note that this method is overridden in subclasses and the return type is refined to S with EfficientSplit, for example scala.collection.IndexedSeqOps.stepper. For Steppers marked with scala.collection.Stepper.EfficientSplit, the converters in scala.jdk.StreamConverters allow creating parallel streams, whereas bare Steppers can be converted only to sequential streams.