Packages

  • package root

    This is the documentation for the Scala standard library.

    This is the documentation for the Scala standard library.

    Package structure

    The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports.

    Notable packages include:

    Other packages exist. See the complete list on the right.

    Additional parts of the standard library are shipped as separate libraries. These include:

    • scala.reflect - Scala's reflection API (scala-reflect.jar)
    • scala.xml - XML parsing, manipulation, and serialization (scala-xml.jar)
    • scala.swing - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
    • scala.util.parsing - Parser combinators (scala-parser-combinators.jar)

    Automatic imports

    Identifiers in the scala package and the scala.Predef object are always in scope by default.

    Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, List is an alias for scala.collection.immutable.List.

    Other aliases refer to classes provided by the underlying platform. For example, on the JVM, String is an alias for java.lang.String.

    Definition Classes
    root
  • package scala

    Core Scala types.

    Core Scala types. They are always available without an explicit import.

    Definition Classes
    root
  • package collection

    Contains the base traits and objects needed to use and extend Scala's collection library.

    Contains the base traits and objects needed to use and extend Scala's collection library.

    Guide

    A detailed guide for using the collections library is available at http://docs.scala-lang.org/overviews/collections/introduction.html. Developers looking to extend the collections library can find a description of its architecture at http://docs.scala-lang.org/overviews/core/architecture-of-scala-collections.html.

    Using Collections

    It is convenient to treat all collections as either a scala.collection.Traversable or scala.collection.Iterable, as these traits define the vast majority of operations on a collection.

    Collections can, of course, be treated as specifically as needed, and the library is designed to ensure that the methods that transform collections will return a collection of the same type:

    scala> val array = Array(1,2,3,4,5,6)
    array: Array[Int] = Array(1, 2, 3, 4, 5, 6)
    
    scala> array map { _.toString }
    res0: Array[String] = Array(1, 2, 3, 4, 5, 6)
    
    scala> val list = List(1,2,3,4,5,6)
    list: List[Int] = List(1, 2, 3, 4, 5, 6)
    
    scala> list map { _.toString }
    res1: List[String] = List(1, 2, 3, 4, 5, 6)

    Creating Collections

    The most common way to create a collection is to use its companion object as a factory. The three most commonly used collections are scala.collection.Seq, scala.collection.immutable.Set, and scala.collection.immutable.Map. They can be used directly as shown below since their companion objects are all available as type aliases in either the scala package or in scala.Predef. New collections are created like this:

    scala> val seq = Seq(1,2,3,4,1)
    seq: Seq[Int] = List(1, 2, 3, 4, 1)
    
    scala> val set = Set(1,2,3,4,1)
    set: scala.collection.immutable.Set[Int] = Set(1, 2, 3, 4)
    
    scala> val map = Map(1 -> "one", 2 -> "two", 3 -> "three", 2 -> "too")
    map: scala.collection.immutable.Map[Int,String] = Map(1 -> one, 2 -> too, 3 -> three)

    It is also typical to prefer the scala.collection.immutable collections over those in scala.collection.mutable; the types aliased in the scala.Predef object are the immutable versions.

    Also note that the collections library was carefully designed to include several implementations of each of the three basic collection types. These implementations have specific performance characteristics which are described in the guide.

    The concrete parallel collections also have specific performance characteristics which are described in the parallel collections guide

    Converting to and from Java Collections

    The scala.collection.JavaConverters object provides a collection of decorators that allow converting between Scala and Java collections using asScala and asJava methods.

    Definition Classes
    scala
  • trait IndexedSeqLike[+A, +Repr] extends SeqLike[A, Repr]

    A template trait for indexed sequences of type IndexedSeq[A].

    A template trait for indexed sequences of type IndexedSeq[A].

    Indexed sequences support constant-time or near constant-time element access and length computation. They are defined in terms of abstract methods apply for indexing and length.

    Indexed sequences do not add any new methods to Seq, but promise efficient implementations of random access patterns.

    This trait just implements iterator in terms of apply and length. However, see IndexedSeqOptimized for an implementation trait that overrides operations to make them run faster under the assumption of fast random access with apply.

    Definition Classes
    collection
  • Elements
  • WithFilter

class Elements extends AbstractIterator[A] with BufferedIterator[A] with Serializable

The class of the iterator returned by the iterator method. multiple take, drop, and slice operations on this iterator are bunched together for better efficiency.

Attributes
protected
Annotations
@SerialVersionUID()
Source
IndexedSeqLike.scala
Linear Supertypes
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Elements
  2. Serializable
  3. Serializable
  4. BufferedIterator
  5. AbstractIterator
  6. Iterator
  7. TraversableOnce
  8. GenTraversableOnce
  9. AnyRef
  10. Any
Implicitly
  1. by MonadOps
  2. by CollectionsHaveToParArray
  3. by any2stringadd
  4. by StringFormat
  5. by Ensuring
  6. by ArrowAssoc
  7. by alternateImplicit
  1. Hide All
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new Elements(start: Int, end: Int)

Type Members

  1. class GroupedIterator[B >: A] extends AbstractIterator[Seq[B]] with Iterator[Seq[B]]

    A flexible iterator for transforming an Iterator[A] into an Iterator[Seq[A]], with configurable sequence size, step, and strategy for dealing with elements which don't fit evenly.

    A flexible iterator for transforming an Iterator[A] into an Iterator[Seq[A]], with configurable sequence size, step, and strategy for dealing with elements which don't fit evenly.

    Typical uses can be achieved via methods grouped and sliding.

    Definition Classes
    Iterator

Value Members

  1. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

    Equivalent to x.hashCode except for boxed numeric types and null.

    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.

    returns

    a hash value consistent with ==

    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from Elements to any2stringadd[Elements] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ++(that: ⇒ Iterator[A]): Iterator[A]

    [use case] Concatenates this iterator with another.

    [use case]

    Concatenates this iterator with another.

    that

    the other iterator

    returns

    a new iterator that first yields the values produced by this iterator followed by the values produced by iterator that.

    Definition Classes
    Iterator
    Full Signature

    def ++[B >: A](that: ⇒ GenTraversableOnce[B]): Iterator[B]

  5. def ->[B](y: B): (Elements, B)
    Implicit
    This member is added by an implicit conversion from Elements to ArrowAssoc[Elements] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: Any): Boolean

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  7. def addString(b: StringBuilder): StringBuilder

    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
    b

    the string builder to which elements are appended.

    returns

    the string builder b to which elements were appended.

    Definition Classes
    TraversableOnce
  8. def addString(b: StringBuilder, sep: String): StringBuilder

    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
    b

    the string builder to which elements are appended.

    sep

    the separator string.

    returns

    the string builder b to which elements were appended.

    Definition Classes
    TraversableOnce
  9. def addString(b: StringBuilder, start: String, sep: String, end: String): StringBuilder

    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)
    b

    the string builder to which elements are appended.

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    the string builder b to which elements were appended.

    Definition Classes
    TraversableOnce
  10. def aggregate[B](z: ⇒ B)(seqop: (B, A) ⇒ B, combop: (B, B) ⇒ B): B

    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 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 })
    B

    the type of accumulated results

    z

    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

    seqop

    an operator used to accumulate results within a partition

    combop

    an associative operator used to combine results from different partitions

    Definition Classes
    TraversableOnceGenTraversableOnce
  11. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

    ClassCastException if the receiver object is not an instance of the erasure of type T0.

  12. def buffered: Elements.this.type

    Creates a buffered iterator from this iterator.

    Creates a buffered iterator from this iterator.

    returns

    a buffered iterator producing the same values as this iterator.

    Definition Classes
    BufferedIteratorIterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

    See also

    scala.collection.BufferedIterator

  13. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
    Note

    not specified by SLS as a member of AnyRef

  14. def collect[B](pf: PartialFunction[A, B]): Iterator[B]

    Creates an iterator by transforming values produced by this iterator with a partial function, dropping those values for which the partial function is not defined.

    Creates an iterator by transforming values produced by this iterator with a partial function, dropping those values for which the partial function is not defined.

    pf

    the partial function which filters and maps the iterator.

    returns

    a new iterator which yields each value x produced by this iterator for which pf is defined the image pf(x).

    Definition Classes
    Iterator
    Annotations
    @migration
    Migration

    (Changed in version 2.8.0) collect has changed. The previous behavior can be reproduced with toSeq.

    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  15. def collectFirst[B](pf: PartialFunction[A, B]): Option[B]

    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.

    pf

    the partial function

    returns

    an option value containing pf applied to the first value for which it is defined, or None if none exists.

    Definition Classes
    TraversableOnce
    Example:
    1. Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)

  16. def contains(elem: Any): Boolean

    Tests whether this iterator contains a given value as an element.

    Tests whether this iterator contains a given value as an element.

    Note: may not terminate for infinite iterators.

    elem

    the element to test.

    returns

    true if this iterator produces some value that is is equal (as determined by ==) to elem, false otherwise.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  17. def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case] Copies selected values produced by this iterator to an array.

    [use case]

    Copies selected values produced by this iterator to an array. Fills the given array xs starting at index start with at most len values produced by this iterator. Copying will stop once either the end of the current iterator is reached, or the end of the array is reached, or len elements have been copied.

    Note: will not terminate for infinite iterators.

    xs

    the array to fill.

    start

    the starting index.

    len

    the maximal number of elements to copy.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Full Signature

    def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Unit

  18. def copyToArray(xs: Array[A]): Unit

    [use case] Copies the elements of this traversable or iterator to an array.

    [use case]

    Copies the elements of this traversable or iterator to an array. Fills the given array xs with values of this traversable or iterator. Copying will stop once either the end of the current traversable or iterator is reached, or the end of the target array is reached.

    Note: will not terminate for infinite iterators.

    xs

    the array to fill.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def copyToArray[B >: A](xs: Array[B]): Unit

  19. def copyToArray(xs: Array[A], start: Int): Unit

    [use case] Copies the elements of this traversable or iterator to an array.

    [use case]

    Copies the elements of this traversable or iterator to an array. Fills the given array xs with values of this traversable or iterator, beginning at index start. Copying will stop once either the end of the current traversable or iterator is reached, or the end of the target array is reached.

    Note: will not terminate for infinite iterators.

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def copyToArray[B >: A](xs: Array[B], start: Int): Unit

  20. def copyToBuffer[B >: A](dest: Buffer[B]): Unit

    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.

    dest

    The buffer to which elements are copied.

    Definition Classes
    TraversableOnce
  21. def corresponds[B](that: GenTraversableOnce[B])(p: (A, B) ⇒ Boolean): Boolean

    Tests whether every element of this iterator relates to the corresponding element of another collection by satisfying a test predicate.

    Tests whether every element of this iterator relates to the corresponding element of another collection by satisfying a test predicate.

    B

    the type of the elements of that

    that

    the other collection

    p

    the test predicate, which relates elements from both collections

    returns

    true if both collections have the same length and p(x, y) is true for all corresponding elements x of this iterator and y of that, otherwise false

    Definition Classes
    Iterator
  22. def count(p: (A) ⇒ Boolean): Int

    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.

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    TraversableOnceGenTraversableOnce
  23. def drop(n: Int): Iterator[A]

    Advances this iterator past the first n elements, or the length of the iterator, whichever is smaller.

    Advances this iterator past the first n elements, or the length of the iterator, whichever is smaller.

    n

    the number of elements to drop

    returns

    an iterator which produces all values of the current iterator, except it omits the first n values.

    Definition Classes
    ElementsIterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  24. def dropWhile(p: (A) ⇒ Boolean): Iterator[A]

    Skips longest sequence of elements of this iterator which satisfy given predicate p, and returns an iterator of the remaining elements.

    Skips longest sequence of elements of this iterator which satisfy given predicate p, and returns an iterator of the remaining elements.

    p

    the predicate used to skip elements.

    returns

    an iterator consisting of the remaining elements

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  25. def duplicate: (Iterator[A], Iterator[A])

    Creates two new iterators that both iterate over the same elements as this iterator (in the same order).

    Creates two new iterators that both iterate over the same elements as this iterator (in the same order). The duplicate iterators are considered equal if they are positioned at the same element.

    Given that most methods on iterators will make the original iterator unfit for further use, this methods provides a reliable way of calling multiple such methods on an iterator.

    returns

    a pair of iterators

    Definition Classes
    Iterator
    Note

    The implementation may allocate temporary storage for elements iterated by one iterator but not yet by the other.

    ,

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

  26. def ensuring(cond: (Elements) ⇒ Boolean, msg: ⇒ Any): Elements
    Implicit
    This member is added by an implicit conversion from Elements to Ensuring[Elements] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  27. def ensuring(cond: (Elements) ⇒ Boolean): Elements
    Implicit
    This member is added by an implicit conversion from Elements to Ensuring[Elements] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  28. def ensuring(cond: Boolean, msg: ⇒ Any): Elements
    Implicit
    This member is added by an implicit conversion from Elements to Ensuring[Elements] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  29. def ensuring(cond: Boolean): Elements
    Implicit
    This member is added by an implicit conversion from Elements to Ensuring[Elements] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  30. final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (that) is a reference to the receiver object (this).

    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:

    • It is consistent: for any non-null instances 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).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  31. def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to eq.

    See also equals in scala.Any.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    AnyRef → Any
  32. def exists(p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for some of the values produced by this iterator.

    Tests whether a predicate holds for some of the values produced by this iterator.

    Note: may not terminate for infinite iterators.

    p

    the predicate used to test elements.

    returns

    true if the given predicate p holds for some of the values produced by this iterator, otherwise false.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  33. def filter(p: (A) ⇒ Boolean): Iterator[A]

    Returns an iterator over all the elements of this iterator that satisfy the predicate p.

    Returns an iterator over all the elements of this iterator that satisfy the predicate p. The order of the elements is preserved.

    p

    the predicate used to test values.

    returns

    an iterator which produces those values of this iterator which satisfy the predicate p.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  34. def filterNot(p: (A) ⇒ Boolean): Iterator[A]

    Creates an iterator over all the elements of this iterator which do not satisfy a predicate p.

    Creates an iterator over all the elements of this iterator which do not satisfy a predicate p.

    p

    the predicate used to test values.

    returns

    an iterator which produces those values of this iterator which do not satisfy the predicate p.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  35. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
    Note

    not specified by SLS as a member of AnyRef

  36. def find(p: (A) ⇒ Boolean): Option[A]

    Finds the first value produced by the iterator satisfying a predicate, if any.

    Finds the first value produced by the iterator satisfying a predicate, if any.

    Note: may not terminate for infinite iterators.

    p

    the predicate used to test values.

    returns

    an option value containing the first value produced by the iterator that satisfies predicate p, or None if none exists.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  37. def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Iterator[B]

    Creates a new iterator by applying a function to all values produced by this iterator and concatenating the results.

    Creates a new iterator by applying a function to all values produced by this iterator and concatenating the results.

    f

    the function to apply on each element.

    returns

    the iterator resulting from applying the given iterator-valued function f to each value produced by this iterator and concatenating the results.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  38. def fold[A1 >: A](z: A1)(op: (A1, A1) ⇒ A1): A1

    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.

    Note: will not terminate for infinite-sized collections.

    A1

    a type parameter for the binary operator, a supertype of A.

    z

    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).

    op

    a binary operator that must be associative.

    returns

    the result of applying the fold operator op between all the elements and z, or z if this traversable or iterator is empty.

    Definition Classes
    TraversableOnceGenTraversableOnce
  39. def foldLeft[B](z: B)(op: (B, A) ⇒ B): B

    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.

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

    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 x1, ..., xn are the elements of this traversable or iterator. Returns z if this traversable or iterator is empty.

    Definition Classes
    TraversableOnceGenTraversableOnce
  40. def foldRight[B](z: B)(op: (A, B) ⇒ B): B

    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: 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.

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

    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 x1, ..., xn are the elements of this traversable or iterator. Returns z if this traversable or iterator is empty.

    Definition Classes
    TraversableOnceGenTraversableOnce
  41. def forall(p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all values produced by this iterator.

    Tests whether a predicate holds for all values produced by this iterator.

    Note: may not terminate for infinite iterators.

    p

    the predicate used to test elements.

    returns

    true if the given predicate p holds for all values produced by this iterator, otherwise false.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  42. def foreach(f: (A) ⇒ Unit): Unit

    [use case] Applies a function f to all values produced by this iterator.

    [use case]

    Applies a function f to all values produced by this iterator.

    f

    the function that is applied for its side-effect to every element. The result of function f is discarded.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Full Signature

    def foreach[U](f: (A) ⇒ U): Unit

  43. def formatted(fmtstr: String): String

    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).

    Implicit
    This member is added by an implicit conversion from Elements to StringFormat[Elements] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  44. final def getClass(): Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  45. def grouped[B >: A](size: Int): GroupedIterator[B]

    Returns an iterator which groups this iterator into fixed size blocks.

    Returns an iterator which groups this iterator into fixed size blocks. Example usages:

    // Returns List(List(1, 2, 3), List(4, 5, 6), List(7)))
    (1 to 7).iterator grouped 3 toList
    // Returns List(List(1, 2, 3), List(4, 5, 6))
    (1 to 7).iterator grouped 3 withPartial false toList
    // Returns List(List(1, 2, 3), List(4, 5, 6), List(7, 20, 25)
    // Illustrating that withPadding's argument is by-name.
    val it2 = Iterator.iterate(20)(_ + 5)
    (1 to 7).iterator grouped 3 withPadding it2.next toList
    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  46. def hasDefiniteSize: Boolean

    Tests whether this Iterator has a known size.

    Tests whether this Iterator has a known size.

    returns

    true for empty Iterators, false otherwise.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  47. def hasNext: Boolean

    Tests whether this iterator can provide another element.

    Tests whether this iterator can provide another element.

    returns

    true if a subsequent call to next will yield an element, false otherwise.

    Definition Classes
    ElementsIterator
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  48. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  49. def head: A

    Returns next element of iterator without advancing beyond it.

    Returns next element of iterator without advancing beyond it.

    Definition Classes
    ElementsBufferedIterator
  50. def headOption: Option[A]

    Returns an option of the next element of an iterator without advancing beyond it.

    Returns an option of the next element of an iterator without advancing beyond it.

    returns

    the next element of this iterator if it has a next element None if it does not

    Definition Classes
    BufferedIterator
  51. def indexOf[B >: A](elem: B, from: Int): Int

    Returns the index of the first occurrence of the specified object in this iterable object after or at some start index.

    Returns the index of the first occurrence of the specified object in this iterable object after or at some start index.

    Note: may not terminate for infinite iterators.

    elem

    element to search for.

    from

    the start index

    returns

    the index >= from of the first occurrence of elem in the values produced by this iterator, or -1 if such an element does not exist until the end of the iterator is reached.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  52. def indexOf[B >: A](elem: B): Int

    Returns the index of the first occurrence of the specified object in this iterable object.

    Returns the index of the first occurrence of the specified object in this iterable object.

    Note: may not terminate for infinite iterators.

    elem

    element to search for.

    returns

    the index of the first occurrence of elem in the values produced by this iterator, or -1 if such an element does not exist until the end of the iterator is reached.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  53. def indexWhere(p: (A) ⇒ Boolean, from: Int): Int

    Returns the index of the first produced value satisfying a predicate, or -1, after or at some start index.

    Returns the index of the first produced value satisfying a predicate, or -1, after or at some start index.

    Note: may not terminate for infinite iterators.

    p

    the predicate to test values

    from

    the start index

    returns

    the index >= from of the first produced value satisfying p, or -1 if such an element does not exist until the end of the iterator is reached.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  54. def indexWhere(p: (A) ⇒ Boolean): Int

    Returns the index of the first produced value satisfying a predicate, or -1.

    Returns the index of the first produced value satisfying a predicate, or -1.

    Note: may not terminate for infinite iterators.

    p

    the predicate to test values

    returns

    the index of the first produced value satisfying p, or -1 if such an element does not exist until the end of the iterator is reached.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  55. def isEmpty: Boolean

    Tests whether this iterator is empty.

    Tests whether this iterator is empty.

    returns

    true if hasNext is false, false otherwise.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  56. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is T0.

    Test whether the dynamic type of the receiver object is T0.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
  57. def isTraversableAgain: Boolean

    Tests whether this Iterator can be repeatedly traversed.

    Tests whether this Iterator can be repeatedly traversed.

    returns

    false

    Definition Classes
    IteratorGenTraversableOnce
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  58. def length: Int

    Returns the number of elements in this iterator.

    Returns the number of elements in this iterator.

    Note: will not terminate for infinite iterators.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on. Using it is undefined and subject to change.

  59. def map[B](f: (A) ⇒ B): Iterator[B]

    Creates a new iterator that maps all produced values of this iterator to new values using a transformation function.

    Creates a new iterator that maps all produced values of this iterator to new values using a transformation function.

    f

    the transformation function

    returns

    a new iterator which transforms every value produced by this iterator by applying the function f to it.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  60. def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

    the largest element of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def max[B >: A](implicit cmp: Ordering[B]): A

    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  61. def maxBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the largest value measured by function f.

    [use case]

    Finds the first element which yields the largest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this traversable or iterator with the largest value measured by function f.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def maxBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  62. def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

    the smallest element of this traversable or iterator

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def min[B >: A](implicit cmp: Ordering[B]): A

    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  63. def minBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the smallest value measured by function f.

    [use case]

    Finds the first element which yields the smallest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this traversable or iterator with the smallest value measured by function f.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def minBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  64. def mkString: String

    Displays all elements of this traversable or iterator in a string.

    Displays all elements of this traversable or iterator in a string.

    returns

    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.

    Definition Classes
    TraversableOnceGenTraversableOnce
  65. def mkString(sep: String): 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.

    sep

    the separator string.

    returns

    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.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("|") = "1|2|3"

  66. def mkString(start: String, sep: String, end: String): String

    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.

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    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.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

  67. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

    true if the argument is not a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  68. def next(): A

    Produces the next element of this iterator.

    Produces the next element of this iterator.

    returns

    the next element of this iterator, if hasNext is true, undefined behavior otherwise.

    Definition Classes
    ElementsIterator
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  69. def nonEmpty: Boolean

    Tests whether the traversable or iterator is not empty.

    Tests whether the traversable or iterator is not empty.

    returns

    true if the traversable or iterator contains at least one element, false otherwise.

    Definition Classes
    TraversableOnceGenTraversableOnce
  70. final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  71. final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
    AnyRef
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  72. def padTo(len: Int, elem: A): Iterator[A]

    [use case] Appends an element value to this iterator until a given target length is reached.

    [use case]

    Appends an element value to this iterator until a given target length is reached.

    len

    the target length

    elem

    the padding value

    returns

    a new iterator consisting of producing all values of this iterator, followed by the minimal number of occurrences of elem so that the number of produced values is at least len.

    Definition Classes
    Iterator
    Full Signature

    def padTo[A1 >: A](len: Int, elem: A1): Iterator[A1]

  73. def partition(p: (A) ⇒ Boolean): (Iterator[A], Iterator[A])

    Partitions this iterator in two iterators according to a predicate.

    Partitions this iterator in two iterators according to a predicate.

    p

    the predicate on which to partition

    returns

    a pair of iterators: the iterator that satisfies the predicate p and the iterator that does not. The relative order of the elements in the resulting iterators is the same as in the original iterator.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

  74. def patch[B >: A](from: Int, patchElems: Iterator[B], replaced: Int): Iterator[B]

    Returns this iterator with patched values.

    Returns this iterator with patched values. Patching at negative indices is the same as patching starting at 0. Patching at indices at or larger than the length of the original iterator appends the patch to the end. If more values are replaced than actually exist, the excess is ignored.

    from

    The start index from which to patch

    patchElems

    The iterator of patch values

    replaced

    The number of values in the original iterator that are replaced by the patch.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, as well as the one passed as a parameter, and use only the iterator that was returned. Using the old iterators is undefined, subject to change, and may result in changes to the new iterator as well.

  75. def product: A

    [use case] Multiplies up the elements of this collection.

    [use case]

    Multiplies up the elements of this collection.

    returns

    the product of all elements in this traversable or iterator 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 traversable or iterator and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def product[B >: A](implicit num: Numeric[B]): B

  76. def reduce[A1 >: A](op: (A1, A1) ⇒ A1): A1

    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.

    A1

    A type parameter for the binary operator, a supertype of A.

    op

    A binary operator that must be associative.

    returns

    The result of applying reduce operator op between all the elements if the traversable or iterator is nonempty.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  77. def reduceLeft[B >: A](op: (B, A) ⇒ B): B

    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.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    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 x1, ..., xn are the elements of this traversable or iterator.

    Definition Classes
    TraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  78. def reduceLeftOption[B >: A](op: (B, A) ⇒ B): Option[B]

    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.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    an option value containing the result of reduceLeft(op) if this traversable or iterator is nonempty, None otherwise.

    Definition Classes
    TraversableOnceGenTraversableOnce
  79. def reduceOption[A1 >: A](op: (A1, A1) ⇒ A1): Option[A1]

    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.

    A1

    A type parameter for the binary operator, a supertype of A.

    op

    A binary operator that must be associative.

    returns

    An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

    Definition Classes
    TraversableOnceGenTraversableOnce
  80. def reduceRight[B >: A](op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this traversable or iterator, going right to left.

    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.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this traversable or iterator, going right to left:

    op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

    where x1, ..., xn are the elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

  81. def reduceRightOption[B >: A](op: (A, B) ⇒ B): Option[B]

    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.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    an option value containing the result of reduceRight(op) if this traversable or iterator is nonempty, None otherwise.

    Definition Classes
    TraversableOnceGenTraversableOnce
  82. def reversed: List[A]
    Attributes
    protected[this]
    Definition Classes
    TraversableOnce
  83. def sameElements(that: Iterator[_]): Boolean

    Tests if another iterator produces the same values as this one.

    Tests if another iterator produces the same values as this one.

    Note: will not terminate for infinite iterators.

    that

    the other iterator

    returns

    true, if both iterators produce the same elements in the same order, false otherwise.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, as well as the one passed as parameter. Using the old iterators is undefined and subject to change.

  84. def scanLeft[B](z: B)(op: (B, A) ⇒ B): Iterator[B]

    Produces a collection containing cumulative results of applying the operator going left to right, including the initial value.

    Produces a collection containing cumulative results of applying the operator going left to right, including the initial value.

    Note: will not terminate for infinite iterators.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the elements in the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    returns

    iterator with intermediate results

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  85. def scanRight[B](z: B)(op: (A, B) ⇒ B): Iterator[B]

    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 iterators.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the elements in the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    returns

    iterator with intermediate results

    Definition Classes
    Iterator
    Example:
    1. Iterator(1, 2, 3, 4).scanRight(0)(_ + _).toList == List(10, 9, 7, 4, 0)
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  86. def seq: Iterator[A]

    A version of this collection with all of the operations implemented sequentially (i.e., in a single-threaded manner).

    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.

    returns

    a sequential view of the collection.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
  87. def size: Int

    The size of this traversable or iterator.

    The size of this traversable or iterator.

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  88. def sizeHintIfCheap: Int

    The size of this collection or iterator, if it can be cheaply computed

    The size of this collection or iterator, if it can be cheaply computed

    returns

    the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply

    Attributes
    protected[collection]
    Definition Classes
    GenTraversableOnce
  89. def slice(from: Int, until: Int): Iterator[A]

    Creates an iterator returning an interval of the values produced by this iterator.

    Creates an iterator returning an interval of the values produced by this iterator.

    from

    the index of the first element in this iterator which forms part of the slice. If negative, the slice starts at zero.

    until

    the index of the first element following the slice. If negative, the slice is empty.

    returns

    an iterator which advances this iterator past the first from elements using drop, and then takes until - from elements, using take.

    Definition Classes
    ElementsIterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  90. def sliceIterator(from: Int, until: Int): Iterator[A]

    Creates an optionally bounded slice, unbounded if until is negative.

    Creates an optionally bounded slice, unbounded if until is negative.

    Attributes
    protected
    Definition Classes
    Iterator
  91. def sliding[B >: A](size: Int, step: Int = 1): GroupedIterator[B]

    Returns an iterator which presents a "sliding window" view of this iterator.

    Returns an iterator which presents a "sliding window" view of this iterator. The first argument is the window size, and the second argument step is how far to advance the window on each iteration. The step defaults to 1.

    The default GroupedIterator can be configured to either pad a partial result to size size or suppress the partial result entirely.

    Example usages:

    // Returns List(List(1, 2, 3), List(2, 3, 4), List(3, 4, 5))
    (1 to 5).iterator.sliding(3).toList
    // Returns List(List(1, 2, 3, 4), List(4, 5))
    (1 to 5).iterator.sliding(4, 3).toList
    // Returns List(List(1, 2, 3, 4))
    (1 to 5).iterator.sliding(4, 3).withPartial(false).toList
    // Returns List(List(1, 2, 3, 4), List(4, 5, 20, 25))
    // Illustrating that withPadding's argument is by-name.
    val it2 = Iterator.iterate(20)(_ + 5)
    (1 to 5).iterator.sliding(4, 3).withPadding(it2.next).toList
    returns

    An iterator producing Seq[B]s 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. This behavior can be configured.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  92. def span(p: (A) ⇒ Boolean): (Iterator[A], Iterator[A])

    Splits this Iterator into a prefix/suffix pair according to a predicate.

    Splits this Iterator into a prefix/suffix pair according to a predicate.

    p

    the test predicate

    returns

    a pair of Iterators consisting of the longest prefix of this whose elements all satisfy p, and the rest of the Iterator.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterators that were returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterators as well.

  93. def sum: A

    [use case] Sums up the elements of this collection.

    [use case]

    Sums up the elements of this collection.

    returns

    the sum of all elements in this traversable or iterator 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 traversable or iterator and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def sum[B >: A](implicit num: Numeric[B]): B

  94. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  95. def take(n: Int): Iterator[A]

    Selects first n values of this iterator.

    Selects first n values of this iterator.

    n

    the number of values to take

    returns

    an iterator producing only the first n values of this iterator, or else the whole iterator, if it produces fewer than n values.

    Definition Classes
    ElementsIterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  96. def takeWhile(p: (A) ⇒ Boolean): Iterator[A]

    Takes longest prefix of values produced by this iterator that satisfy a predicate.

    Takes longest prefix of values produced by this iterator that satisfy a predicate.

    p

    The predicate used to test elements.

    returns

    An iterator returning the values produced by this iterator, until this iterator produces a value that does not satisfy the predicate p.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  97. def to[Col[_]]: Col[A]

    [use case] Converts this traversable or iterator into another by copying all elements.

    [use case]

    Converts this traversable or iterator into another by copying all elements.

    Note: will not terminate for infinite iterators.

    Col

    The collection type to build.

    returns

    a new collection containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A]]): Col[A]

  98. def toArray: Array[A]

    [use case] Converts this traversable or iterator to an array.

    [use case]

    Converts this traversable or iterator to an array.

    Note: will not terminate for infinite iterators.

    returns

    an array containing all elements of this traversable or iterator. An ClassTag must be available for the element type of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def toArray[B >: A](implicit arg0: ClassTag[B]): Array[B]

  99. def toBuffer[B >: A]: Buffer[B]

    Uses the contents of this traversable or iterator to create a new mutable buffer.

    Uses the contents of this traversable or iterator to create a new mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  100. def toIndexedSeq: immutable.IndexedSeq[A]

    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.

    returns

    an indexed sequence containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  101. def toIterable: Iterable[A]

    Converts this traversable or iterator to an iterable collection.

    Converts this traversable or iterator to an iterable collection. Note that the choice of target Iterable is lazy in this default implementation as this TraversableOnce may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterable containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  102. def toIterator: Iterator[A]

    Returns an Iterator over the elements in this traversable or iterator.

    Returns an Iterator over the elements in this traversable or iterator. Will return the same Iterator if this instance is already an Iterator.

    Note: will not terminate for infinite iterators.

    returns

    an Iterator containing all elements of this traversable or iterator.

    Definition Classes
    IteratorGenTraversableOnce
  103. def toList: List[A]

    Converts this traversable or iterator to a list.

    Converts this traversable or iterator to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  104. def toMap[T, U]: Map[T, U]

    [use case] Converts this traversable or iterator to a map.

    [use case]

    Converts this traversable or iterator 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.

    Note: will not terminate for infinite iterators.

    returns

    a map of type immutable.Map[T, U] containing all key/value pairs of type (T, U) of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

    def toMap[T, U](implicit ev: <:<[A, (T, U)]): immutable.Map[T, U]

  105. def toParArray: ParArray[T]
    Implicit
    This member is added by an implicit conversion from Elements to CollectionsHaveToParArray[Elements, T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (Elements) ⇒ GenTraversableOnce[T] is in scope.
    Definition Classes
    CollectionsHaveToParArray
  106. def toSeq: Seq[A]

    Converts this traversable or iterator to a sequence.

    Converts this traversable or iterator to a sequence. As with toIterable, it's lazy in this default implementation, as this TraversableOnce may be lazy and unevaluated.

    Note: will not terminate for infinite-sized collections.

    returns

    a sequence containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  107. def toSet[B >: A]: immutable.Set[B]

    Converts this traversable or iterator to a set.

    Converts this traversable or iterator to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  108. def toStream: immutable.Stream[A]

    Converts this traversable or iterator to a stream.

    Converts this traversable or iterator to a stream.

    returns

    a stream containing all elements of this traversable or iterator.

    Definition Classes
    IteratorGenTraversableOnce
  109. def toString(): String

    Converts this iterator to a string.

    Converts this iterator to a string.

    returns

    "<iterator>" whether or not the iterator is empty.

    Definition Classes
    Iterator → AnyRef → Any
    Note

    Reuse: The iterator remains valid for further use whatever result is returned.

  110. def toTraversable: Traversable[A]

    Converts this traversable or iterator to an unspecified Traversable.

    Converts this traversable or iterator to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

    Note: will not terminate for infinite iterators.

    returns

    a Traversable containing all elements of this traversable or iterator.

    Definition Classes
    IteratorTraversableOnceGenTraversableOnce
  111. def toVector: Vector[A]

    Converts this traversable or iterator to a Vector.

    Converts this traversable or iterator to a Vector.

    Note: will not terminate for infinite-sized collections.

    returns

    a vector containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  112. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  113. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  114. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  115. def withFilter(p: (A) ⇒ Boolean): Iterator[A]

    Creates an iterator over all the elements of this iterator that satisfy the predicate p.

    Creates an iterator over all the elements of this iterator that satisfy the predicate p. The order of the elements is preserved.

    Note: withFilter is the same as filter on iterators. It exists so that for-expressions with filters work over iterators.

    p

    the predicate used to test values.

    returns

    an iterator which produces those values of this iterator which satisfy the predicate p.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  116. def zip[B](that: Iterator[B]): Iterator[(A, B)]

    Creates an iterator formed from this iterator and another iterator by combining corresponding values in pairs.

    Creates an iterator formed from this iterator and another iterator by combining corresponding values in pairs. If one of the two iterators is longer than the other, its remaining elements are ignored.

    that

    The iterator providing the second half of each result pair

    returns

    a new iterator containing pairs consisting of corresponding elements of this iterator and that. The number of elements returned by the new iterator is the minimum of the number of elements returned by this iterator and that.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, as well as the one passed as a parameter, and use only the iterator that was returned. Using the old iterators is undefined, subject to change, and may result in changes to the new iterator as well.

  117. def zipAll[B](that: Iterator[B], thisElem: A, thatElem: B): Iterator[(A, B)]

    [use case] Creates an iterator formed from this iterator and another iterator by combining corresponding elements in pairs.

    [use case]

    Creates an iterator formed from this iterator and another iterator by combining corresponding elements in pairs. If one of the two iterators is shorter than the other, placeholder elements are used to extend the shorter iterator to the length of the longer.

    that

    iterator that may have a different length as the self iterator.

    thisElem

    element thisElem is used to fill up the resulting iterator if the self iterator is shorter than that

    thatElem

    element thatElem is used to fill up the resulting iterator if that is shorter than the self iterator

    returns

    a new iterator containing pairs consisting of corresponding values of this iterator and that. The length of the returned iterator is the maximum of the lengths of this iterator and that. If this iterator is shorter than that, thisElem values are used to pad the result. If that is shorter than this iterator, thatElem values are used to pad the result.

    Definition Classes
    Iterator
    Full Signature

    def zipAll[B, A1 >: A, B1 >: B](that: Iterator[B], thisElem: A1, thatElem: B1): Iterator[(A1, B1)]

  118. def zipWithIndex: Iterator[(A, Int)]

    Creates an iterator that pairs each element produced by this iterator with its index, counting from 0.

    Creates an iterator that pairs each element produced by this iterator with its index, counting from 0.

    returns

    a new iterator containing pairs consisting of corresponding elements of this iterator and their indices.

    Definition Classes
    Iterator
    Note

    Reuse: After calling this method, one should discard the iterator it was called on, and use only the iterator that was returned. Using the old iterator is undefined, subject to change, and may result in changes to the new iterator as well.

  119. def [B](y: B): (Elements, B)
    Implicit
    This member is added by an implicit conversion from Elements to ArrowAssoc[Elements] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Shadowed Implicit Value Members

  1. def filter(p: (A) ⇒ Boolean): TraversableOnce[A]
    Implicit
    This member is added by an implicit conversion from Elements to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (elements: MonadOps[A]).filter(p)
    Definition Classes
    MonadOps
  2. def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): TraversableOnce[B]
    Implicit
    This member is added by an implicit conversion from Elements to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (elements: MonadOps[A]).flatMap(f)
    Definition Classes
    MonadOps
  3. def map[B](f: (A) ⇒ B): TraversableOnce[B]
    Implicit
    This member is added by an implicit conversion from Elements to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (elements: MonadOps[A]).map(f)
    Definition Classes
    MonadOps
  4. def withFilter(p: (A) ⇒ Boolean): Iterator[A]
    Implicit
    This member is added by an implicit conversion from Elements to MonadOps[A] performed by method MonadOps in scala.collection.TraversableOnce.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (elements: MonadOps[A]).withFilter(p)
    Definition Classes
    MonadOps

Deprecated Value Members

  1. def /:[B](z: B)(op: (B, A) ⇒ B): B

    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.

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

    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 x1, ..., xn are the elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldLeft instead of /:

  2. def :\[B](z: B)(op: (A, B) ⇒ B): B

    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
    B

    the result type of the binary operator.

    z

    the start value

    op

    the binary operator

    returns

    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 x1, ..., xn are the elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldRight instead of :\

Inherited from Serializable

Inherited from java.io.Serializable

Inherited from BufferedIterator[A]

Inherited from AbstractIterator[A]

Inherited from Iterator[A]

Inherited from TraversableOnce[A]

Inherited from GenTraversableOnce[A]

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion MonadOps from Elements to MonadOps[A]

Inherited by implicit conversion CollectionsHaveToParArray from Elements to CollectionsHaveToParArray[Elements, T]

Inherited by implicit conversion any2stringadd from Elements to any2stringadd[Elements]

Inherited by implicit conversion StringFormat from Elements to StringFormat[Elements]

Inherited by implicit conversion Ensuring from Elements to Ensuring[Elements]

Inherited by implicit conversion ArrowAssoc from Elements to ArrowAssoc[Elements]

Inherited by implicit conversion alternateImplicit from Elements to ForceImplicitAmbiguity

Ungrouped