scala.collection.mutable

# Traversable

#### trait Traversable [A] extends Traversable[A] with GenericTraversableTemplate[A, Traversable] with TraversableLike[A, Traversable[A]] with Mutable

A trait for traversable collections that can be mutated.

This is a base trait of all kinds of mutable Scala collections. It implements the behavior common to all collections, in terms of a method `foreach` with signature:

        def foreach[U](f: Elem => U): Unit

Collection classes mixing in this trait provide a concrete `foreach` method which traverses all the elements contained in the collection, applying a given function to each. They also need to provide a method `newBuilder` which creates a builder for collections of the same kind.

A traversable class might or might not have two properties: strictness and orderedness. Neither is represented as a type.

The instances of a strict collection class have all their elements computed before they can be used as values. By contrast, instances of a non-strict collection class may defer computation of some of their elements until after the instance is available as a value. A typical example of a non-strict collection class is a `scala.collection.immutable.Stream`. A more general class of examples are `TraversableViews`.

If a collection is an instance of an ordered collection class, traversing its elements with `foreach` will always visit elements in the same order, even for different runs of the program. If the class is not ordered, `foreach` can visit elements in different orders for different runs (but it will keep the same order in the same run).'

A typical example of a collection class which is not ordered is a `HashMap` of objects. The traversal order for hash maps will depend on the hash codes of its elements, and these hash codes might differ from one run to the next. By contrast, a `LinkedHashMap` is ordered because it's `foreach` method visits elements in the order they were inserted into the `HashMap`.

Source
  Traversable.scala

Linear Supertypes
Mutable, Traversable[A], GenTraversable[A], GenericTraversableTemplate[A, Traversable], TraversableLike[A, Traversable[A]], GenTraversableLike[A, Traversable[A]], Parallelizable[A, ParIterable[A]], TraversableOnce[A], GenTraversableOnce[A], FilterMonadic[A, Traversable[A]], HasNewBuilder[A, Traversable[A]], AnyRef, Any
Known Subclasses
ArrayBuffer, ArraySeq, ArrayStack, BitSet, Buffer, BufferProxy, BufferWrapper, ConcurrentMap, Content, DefaultMapModel, DoubleLinkedList, DroppedWhile, Filtered, HashMap, HashSet, History, ImmutableMapAdaptor, ImmutableSetAdaptor, IndexedSeq, IndexedSeqView, Indices, Iterable, JConcurrentMapWrapper, JDictionaryWrapper, JListWrapper, JMapWrapper, JMapWrapperLike, JPropertiesWrapper, JSetWrapper, LinearSeq, LinkedHashMap, LinkedHashSet, LinkedList, ListBuffer, ListMap, Map, MapProxy, MultiMap, MutableList, NodeBuffer, ObservableBuffer, ObservableMap, ObservableSet, OpenHashMap, PicklerEnv, PriorityQueue, PriorityQueueProxy, Queue, QueueProxy, RefBuffer, ResizableArray, Reversed, RevertibleHistory, Script, SelectionSet, Seq, Set, SetProxy, Sliced, Stack, StackProxy, StringBuilder, SynchronizedBuffer, SynchronizedMap, SynchronizedPriorityQueue, SynchronizedQueue, SynchronizedSet, SynchronizedStack, SystemProperties, TakenWhile, Transformed, UnPicklerEnv, UnrolledBuffer, WeakHashMap, WithDefault, WrappedArray, columns, indices, ofBoolean, ofByte, ofChar, ofDouble, ofFloat, ofInt, ofLong, ofRef, ofShort, ofUnit, pages, rows
Ordering

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2. By inheritance

Inherited

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2. Show all

1. Traversable
2. Mutable
3. Traversable
4. GenTraversable
5. GenericTraversableTemplate
6. TraversableLike
7. GenTraversableLike
8. Parallelizable
9. TraversableOnce
10. GenTraversableOnce
11. FilterMonadic
12. HasNewBuilder
13. AnyRef
14. Any

Visibility

1. Public
2. All

### Type Members

1. #### type Self = Traversable[A]

   The type implementing this traversable

   The type implementing this traversable

   Attributes
     protected
   Definition Classes
     TraversableLike

2. #### class WithFilter extends FilterMonadic[A, Repr]

   A class supporting filtered operations.

### Abstract Value Members

1. #### def foreach [U] (f: (A) ⇒ U): Unit

   Applies a function `f` to all elements of this collection.

   Applies a function `f` to all elements of this collection.

   U

     the type parameter describing the result of function `f`. This result will always be ignored. Typically `U` is `Unit`, but this is not necessary.

   f

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

   Attributes
     abstract
   Definition Classes
     GenericTraversableTemplate

### Concrete Value Members

1. #### def != (arg0: AnyRef): Boolean

   Attributes
     final
   Definition Classes
     AnyRef

2. #### def != (arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

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

   Attributes
     final
   Definition Classes
     Any

3. #### def ## (): Int

   Equivalent to `x.hashCode` except for boxed numeric types.

   Equivalent to `x.hashCode` except for boxed numeric types. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them.

   returns

     a hash value consistent with ==

   Attributes
     final
   Definition Classes
     AnyRef → Any

4. #### def ++ [B >: A, That] (that: TraversableOnce[B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

   Definition Classes
     TraversableLike
   Annotations
     @bridge()

5. #### def ++ [B] (that: GenTraversableOnce[B]): CC[B]

   [use case] Concatenates this collection with the elements of a traversable collection.

   [use case]

   Concatenates this collection with the elements of a traversable collection.

   B

     the element type of the returned collection.

   that

     the traversable to append.

   returns

     a new collection of type `That` which contains all elements of this collection followed by all elements of `that`.

   Attributes
     abstract
   Definition Classes
     GenTraversableLike

6. #### def ++ [B >: A, That] (that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

   Concatenates this collection with the elements of a traversable collection.

   Concatenates this collection with the elements of a traversable collection.

   B

     the element type of the returned collection.

   That

     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.

   that

     the traversable to append.

   bf

     an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

   returns

     a new collection of type `That` which contains all elements of this collection followed by all elements of `that`.

   Definition Classes
     TraversableLike → GenTraversableLike

7. #### def ++: [B >: A, That] (that: Traversable[B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

   This overload exists because: for the implementation of ++: we should reuse that of ++ because many collections override it with more efficient versions.

   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.

   Definition Classes
     TraversableLike

8. #### def ++: [B] (that: TraversableOnce[B]): CC[B]

   [use case] Concatenates this collection with the elements of a traversable collection.

   [use case]

   Concatenates this collection with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.

   B

     the element type of the returned collection.

   that

     the traversable to append.

   returns

     a new collection of type `That` which contains all elements of this collection followed by all elements of `that`.

   Attributes
     abstract
   Definition Classes
     TraversableLike

9. #### def ++: [B >: A, That] (that: TraversableOnce[B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

   Concatenates this collection with the elements of a traversable collection.

   Concatenates this collection with the elements of a traversable collection. It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one.

   B

     the element type of the returned collection.

   That

     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.

   that

     the traversable to append.

   bf

     an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

   returns

     a new collection of type `That` which contains all elements of this collection followed by all elements of `that`.

   Definition Classes
     TraversableLike

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

    Applies a binary operator to a start value and all elements of this collection, going left to right.

    Applies a binary operator to a start value and all elements of this collection, going left to right.

    Note: `/:` is alternate syntax for `foldLeft`; `z /: xs` is the same as `xs foldLeft 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.

    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 collection, 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 collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

11. #### def /:\ [A1 >: A] (z: A1)(op: (A1, A1) ⇒ A1): A1

    A syntactic sugar for out of order folding.

    A syntactic sugar for out of order folding. See `fold`.

    Definition Classes
      GenTraversableOnce

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

    Applies a binary operator to all elements of this collection and a start value, going right to left.

    Applies a binary operator to all elements of this collection 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.

    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 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 collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

13. #### def == (arg0: AnyRef): Boolean

    Attributes
      final
    Definition Classes
      AnyRef

14. #### def == (arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality.

    returns

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

    Attributes
      final
    Definition Classes
      Any

15. #### def addString (b: StringBuilder): StringBuilder

    Appends all elements of this collection to a string builder.

    Appends all elements of this collection to a string builder. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this collection without any separator string.

    b

      the string builder to which elements are appended.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableOnce

16. #### def addString (b: StringBuilder, sep: String): StringBuilder

    Appends all elements of this collection to a string builder using a separator string.

    Appends all elements of this collection 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 collection, separated by the string `sep`.

    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

17. #### def addString (b: StringBuilder, start: String, sep: String, end: String): StringBuilder

    Appends all elements of this collection to a string builder using start, end, and separator strings.

    Appends all elements of this collection 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 collection are separated by the string `sep`.

    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

18. #### 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 has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using `seqop` to update the result, and then applies `combop` to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so `combop` may be invoked arbitrary number of times.

    For example, one might want to process some elements and then produce a `Set`. In this case, `seqop` would process an element and append it to the list, while `combop` would concatenate two lists from different partitions together. The initial value `z` would be an empty set.

           pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)

    Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).

    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)

    seqop

      an operator used to accumulate results within a partition

    combop

      an associative operator used to combine results from different partitions

    Definition Classes
      TraversableOnce → GenTraversableOnce

19. #### 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.

    Attributes
      final
    Definition Classes
      Any

20. #### 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()

21. #### def collect [B] (pf: PartialFunction[A, B]): CC[B]

    [use case] Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.

    [use case]

    Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.

    B

      the element type of the returned collection.

    pf

      the partial function which filters and maps the collection.

    returns

      a new collection of type `That` resulting from applying the partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Attributes
      abstract
    Definition Classes
      GenTraversableLike

22. #### def collect [B, That] (pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

    Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.

    Builds a new collection by applying a partial function to all elements of this collection on which the function is defined.

    B

      the element type of the returned collection.

    That

      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.

    pf

      the partial function which filters and maps the collection.

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      a new collection of type `That` resulting from applying the partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

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

    Finds the first element of the collection for which the given partial function is defined, and applies the partial function to it.

    Finds the first element of the collection 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)`

24. #### def companion : GenericCompanion[Traversable]

    The factory companion object that builds instances of class CC.

    The factory companion object that builds instances of class CC. (or its `Iterable` superclass where class CC is not a `Seq`.)

    Definition Classes
      Traversable → Traversable → GenTraversable → GenericTraversableTemplate

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

    [use case] Copies elements of this collection to an array.

    [use case]

    Copies elements of this collection to an array. Fills the given array `xs` with at most `len` elements of this collection, starting at position `start`. Copying will stop once either the end of the current collection is reached, or the end of the array is reached, or `len` elements have been copied.

    xs

      the array to fill.

    start

      the starting index.

    len

      the maximal number of elements to copy.

    Attributes
      abstract
    Definition Classes
      TraversableLike

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

    Copies elements of this collection to an array.

    Copies elements of this collection to an array. Fills the given array `xs` with at most `len` elements of this collection, starting at position `start`. Copying will stop once either the end of the current collection is reached, or the end of the array is reached, or `len` elements have been copied.

    Note: will not terminate for infinite-sized collections.

    B

      the type of the elements of the array.

    xs

      the array to fill.

    start

      the starting index.

    len

      the maximal number of elements to copy.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

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

    [use case] Copies values of this collection to an array.

    [use case]

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

    xs

      the array to fill.

    Attributes
      abstract
    Definition Classes
      GenTraversableOnce

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

    Copies values of this collection to an array.

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

    Note: will not terminate for infinite-sized collections.

    B

      the type of the elements of the array.

    xs

      the array to fill.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    [use case] Copies values of this collection to an array.

    [use case]

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

    xs

      the array to fill.

    start

      the starting index.

    Attributes
      abstract
    Definition Classes
      GenTraversableOnce

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

    Copies values of this collection to an array.

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

    Note: will not terminate for infinite-sized collections.

    B

      the type of the elements of the array.

    xs

      the array to fill.

    start

      the starting index.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Copies all elements of this collection to a buffer.

    Copies all elements of this collection to a buffer.

    Note: will not terminate for infinite-sized collections.

    dest

      The buffer to which elements are copied.

    Definition Classes
      TraversableOnce

32. #### def count (p: (A) ⇒ Boolean): Int

    Counts the number of elements in the collection which satisfy a predicate.

    Counts the number of elements in the collection which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      the number of elements satisfying the predicate `p`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

33. #### def drop (n: Int): Traversable[A]

    Selects all elements except first n ones.

    Selects all elements except first n ones.

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

    n

      the number of elements to drop from this collection.

    returns

      a collection consisting of all elements of this collection except the first `n` ones, or else the empty collection, if this collection has less than `n` elements.

    Definition Classes
      TraversableLike → GenTraversableLike

34. #### def dropWhile (p: (A) ⇒ Boolean): Traversable[A]

    Drops longest prefix of elements that satisfy a predicate.

    Drops longest prefix of elements that satisfy a predicate.

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

    p

      The predicate used to test elements.

    returns

      the longest suffix of this collection whose first element does not satisfy the predicate `p`.

    Definition Classes
      TraversableLike → GenTraversableLike

35. #### def eq (arg0: AnyRef): Boolean

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

    The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

    - 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.

    Attributes
      final
    Definition Classes
      AnyRef

36. #### def equals (arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. See equals in Any.

    returns

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

    Definition Classes
      AnyRef → Any

37. #### def exists (p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for some of the elements of this collection.

    Tests whether a predicate holds for some of the elements of this collection.

    Note: may not terminate for infinite-sized collections.

    p

      the predicate used to test elements.

    returns

      `true` if the given predicate `p` holds for some of the elements of this collection, otherwise `false`.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

38. #### def filter (p: (A) ⇒ Boolean): Traversable[A]

    Selects all elements of this collection which satisfy a predicate.

    Selects all elements of this collection which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new collection consisting of all elements of this collection that satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

39. #### def filterNot (p: (A) ⇒ Boolean): Traversable[A]

    Selects all elements of this collection which do not satisfy a predicate.

    Selects all elements of this collection which do not satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new collection consisting of all elements of this collection that do not satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      TraversableLike → GenTraversableLike

40. #### 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()

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

    Finds the first element of the collection satisfying a predicate, if any.

    Finds the first element of the 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.

    p

      the predicate used to test elements.

    returns

      an option value containing the first element in the collection that satisfies `p`, or `None` if none exists.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

42. #### def flatMap [B] (f: (A) ⇒ GenTraversableOnce[B]): CC[B]

    [use case] Builds a new collection by applying a function to all elements of this collection and concatenating the results.

    [use case]

    Builds a new collection by applying a function to all elements of this collection and concatenating the results.

    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new collection of type `That` resulting from applying the given collection-valued function `f` to each element of this collection and concatenating the results.

    Attributes
      abstract
    Definition Classes
      GenTraversableLike

43. #### def flatMap [B, That] (f: (A) ⇒ GenTraversableOnce[B])(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

    Builds a new collection by applying a function to all elements of this collection and concatenating the results.

    Builds a new collection by applying a function to all elements of this collection and concatenating the results.

    B

      the element type of the returned collection.

    That

      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.

    f

      the function to apply to each element.

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      a new collection of type `That` resulting from applying the given collection-valued function `f` to each element of this collection and concatenating the results.

    Definition Classes
      TraversableLike → GenTraversableLike → FilterMonadic

44. #### def flatten [B] : CC[B]

    [use case] Converts this collection of traversable collections into a collection in which all element collections are concatenated.

    [use case]

    Converts this collection of traversable collections into a collection in which all element collections are concatenated.

    B

      the type of the elements of each traversable collection.

    returns

      a new collection resulting from concatenating all element collections.

    Attributes
      abstract
    Definition Classes
      GenericTraversableTemplate

45. #### def flatten [B] (implicit asTraversable: (A) ⇒ TraversableOnce[B]): Traversable[B]

    Converts this collection of traversable collections into a collection in which all element collections are concatenated.

    Converts this collection of traversable collections into a collection in which all element collections are concatenated.

    B

      the type of the elements of each traversable collection.

    asTraversable

      an implicit conversion which asserts that the element type of this collection is a `Traversable`.

    returns

      a new collection resulting from concatenating all element collections.

    Definition Classes
      Traversable → GenericTraversableTemplate
    Annotations
      @bridge()

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

    Folds the elements of this sequence using the specified associative binary operator.

    Folds the elements of this sequence using the specified associative binary operator. The order in which the elements are reduced is unspecified and may be nondeterministic.

    Note this method has a different signature than the `foldLeft` and `foldRight` methods of the trait `Traversable`. The result of folding may only be a supertype of this parallel collection's type parameter `T`.

    z

      a neutral element for the fold operation, it may be added to the result an arbitrary number of times, not changing 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 fold operator `op` between all the elements and `z`

    Definition Classes
      TraversableOnce → GenTraversableOnce

47. #### def foldLeft [B] (z: B)(op: (B, A) ⇒ B): B

    Applies a binary operator to a start value and all elements of this collection, going left to right.

    Applies a binary operator to a start value and all elements of this collection, 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 collection, 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 collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

48. #### def foldRight [B] (z: B)(op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this collection and a start value, going right to left.

    Applies a binary operator to all elements of this 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.

    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 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 collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

49. #### def forall (p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all elements of this collection.

    Tests whether a predicate holds for all elements of this collection.

    Note: may not terminate for infinite-sized collections.

    p

      the predicate used to test elements.

    returns

      `true` if the given predicate `p` holds for all elements of this collection, otherwise `false`.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

50. #### def foreach (f: (A) ⇒ Unit): Unit

    [use case] Applies a function `f` to all elements of this collection.

    [use case]

    Applies a function `f` to all elements of this collection.

    f

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

    Attributes
      abstract
    Definition Classes
      GenericTraversableTemplate

51. #### def genericBuilder [B] : Builder[B, Traversable[B]]

    The generic builder that builds instances of CC at arbitrary element types.

    The generic builder that builds instances of CC at arbitrary element types.

    Definition Classes
      GenericTraversableTemplate

52. #### def getClass (): java.lang.Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

      a representation that corresponds to the dynamic class of the receiver object.

    Attributes
      final
    Definition Classes
      AnyRef → Any

53. #### def groupBy [K] (f: (A) ⇒ K): Map[K, Traversable[A]]

    Partitions this collection into a map of collections according to some discriminator function.

    Partitions this collection into a map of 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 collection.

    K

      the type of keys returned by the discriminator function.

    f

      the discriminator function.

    returns

      A map from keys to collections such that the following invariant holds:

                          (xs partition f)(k) = xs filter (x => f(x) == k)

      That is, every key `k` is bound to a collection of those elements `x` for which `f(x)` equals `k`.

    Definition Classes
      TraversableLike → GenTraversableLike

54. #### def hasDefiniteSize : Boolean

    Tests whether this collection is known to have a finite size.

    Tests whether this collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as `Stream`, the predicate returns `true` if all elements have been computed. It returns `false` if the stream is not yet evaluated to the end.

    Note: many collection methods will not work on collections of infinite sizes.

    returns

      `true` if this collection is known to have finite size, `false` otherwise.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

55. #### def hashCode (): Int

    The hashCode method for reference types.

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

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any

56. #### def head : A

    Selects the first element of this collection.

    Selects the first element of this collection.

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

    returns

      the first element of this collection.

    Definition Classes
      TraversableLike → GenTraversableLike

57. #### def headOption : Option[A]

    Optionally selects the first element.

    Optionally selects the first element.

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

    returns

      the first element of this collection if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableLike

58. #### def init : Traversable[A]

    Selects all elements except the last.

    Selects all elements except the last.

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

    returns

      a collection consisting of all elements of this collection except the last one.

    Definition Classes
      TraversableLike

59. #### def inits : Iterator[Traversable[A]]

    Iterates over the inits of this collection.

    Iterates over the inits of this collection. The first value will be this collection and the final one will be an empty collection, with the intervening values the results of successive applications of `init`.

    returns

      an iterator over all the inits of this collection

    Definition Classes
      TraversableLike
    Example:

    1. `List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)`

60. #### def isEmpty : Boolean

    Tests whether this collection is empty.

    Tests whether this collection is empty.

    returns

      `true` if the collection contain no elements, `false` otherwise.

    Definition Classes
      TraversableLike → TraversableOnce → GenTraversableOnce

61. #### 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.

    Attributes
      final
    Definition Classes
      Any

62. #### def isTraversableAgain : Boolean

    Tests whether this collection can be repeatedly traversed.

    Tests whether this collection can be repeatedly traversed.

    returns

      `true`

    Attributes
      final
    Definition Classes
      GenTraversableLike → GenTraversableOnce

63. #### def last : A

    Selects the last element.

    Selects the last element.

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

    returns

      The last element of this collection.

    Definition Classes
      TraversableLike

64. #### def lastOption : Option[A]

    Optionally selects the last element.

    Optionally selects the last element.

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

    returns

      the last element of this collection$ if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableLike

65. #### def map [B] (f: (A) ⇒ B): CC[B]

    [use case] Builds a new collection by applying a function to all elements of this collection.

    [use case]

    Builds a new collection by applying a function to all elements of this collection.

    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new collection of type `That` resulting from applying the given function `f` to each element of this collection and collecting the results.

    Attributes
      abstract
    Definition Classes
      GenTraversableLike

66. #### def map [B, That] (f: (A) ⇒ B)(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

    Builds a new collection by applying a function to all elements of this collection.

    Builds a new collection by applying a function to all elements of this collection.

    B

      the element type of the returned collection.

    That

      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.

    f

      the function to apply to each element.

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      a new collection of type `That` resulting from applying the given function `f` to each element of this collection and collecting the results.

    Definition Classes
      TraversableLike → GenTraversableLike → FilterMonadic

67. #### def max : A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

      the largest element of this collection with respect to the ordering `cmp`.

    Attributes
      abstract
    Definition Classes
      GenTraversableOnce

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

    Finds the largest element.

    Finds the largest element.

    B

      The type over which the ordering is defined.

    cmp

      An ordering to be used for comparing elements.

    returns

      the largest element of this collection with respect to the ordering `cmp`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Definition Classes
      TraversableOnce → GenTraversableOnce

70. #### def min : A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

      the smallest element of this collection with respect to the ordering `cmp`.

    Attributes
      abstract
    Definition Classes
      GenTraversableOnce

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

    Finds the smallest element.

    Finds the smallest element.

    B

      The type over which the ordering is defined.

    cmp

      An ordering to be used for comparing elements.

    returns

      the smallest element of this collection with respect to the ordering `cmp`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Definition Classes
      TraversableOnce → GenTraversableOnce

73. #### def mkString : String

    Displays all elements of this collection in a string.

    Displays all elements of this collection in a string.

    returns

      a string representation of this collection. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this collection follow each other without any separator string.

    Definition Classes
      TraversableOnce → GenTraversableOnce

74. #### def mkString (sep: String): String

    Displays all elements of this collection in a string using a separator string.

    Displays all elements of this collection in a string using a separator string.

    sep

      the separator string.

    returns

      a string representation of this collection. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this collection are separated by the string `sep`.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("|") = "1|2|3"`

75. #### def mkString (start: String, sep: String, end: String): String

    Displays all elements of this collection in a string using start, end, and separator strings.

    Displays all elements of this collection 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 collection. 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 collection are separated by the string `sep`.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"`

76. #### 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.

    Attributes
      final
    Definition Classes
      AnyRef

77. #### def newBuilder : Builder[A, Traversable[A]]

    The builder that builds instances of type CC[A]

    The builder that builds instances of type CC[A]

    Attributes
      protected[this]
    Definition Classes
      GenericTraversableTemplate → HasNewBuilder

78. #### def nonEmpty : Boolean

    Tests whether the collection is not empty.

    Tests whether the collection is not empty.

    returns

      `true` if the collection contains at least one element, `false` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

79. #### 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.

    Attributes
      final
    Definition Classes
      AnyRef

80. #### 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.

    Attributes
      final
    Definition Classes
      AnyRef

81. #### def par : ParIterable[A]

    Returns a parallel implementation of this collection.

    Returns a parallel implementation of this collection.

    For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, `par` takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.

    Specific collections (e.g. `ParArray` or `mutable.ParHashMap`) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, `par` takes constant or sublinear time.

    All parallel collections return a reference to themselves.

    returns

      a parallel implementation of this collection

    Definition Classes
      Parallelizable

82. #### def parCombiner : Combiner[A, ParIterable[A]]

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    returns

      a combiner for the parallel collection of type `ParRepr`

    Attributes
      protected[this]
    Definition Classes
      TraversableLike → Parallelizable

83. #### def partition (p: (A) ⇒ Boolean): (Traversable[A], Traversable[A])

    Partitions this collection in two collections according to a predicate.

    Partitions this collection in two collections according to a predicate.

    p

      the predicate on which to partition.

    returns

      a pair of collections: the first collection consists of all elements that satisfy the predicate `p` and the second collection consists of all elements that don't. The relative order of the elements in the resulting collections is the same as in the original collection.

    Definition Classes
      TraversableLike → GenTraversableLike

84. #### 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 of this collection with respect to the `*` operator in `num`.

    Attributes
      abstract
    Definition Classes
      GenTraversableOnce

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

    Multiplies up the elements of this collection.

    Multiplies up the elements of this collection.

    B

      the result type of the `*` operator.

    num

      an implicit parameter defining a set of numeric operations which includes the `*` operator to be used in forming the product.

    returns

      the product of all elements of this collection with respect to the `*` operator in `num`.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Reduces the elements of this sequence using the specified associative binary operator.

    Reduces the elements of this sequence using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    Note this method has a different signature than the `reduceLeft` and `reduceRight` methods of the trait `Traversable`. The result of reducing may only be a supertype of this parallel collection's type parameter `T`.

    op

      A binary operator that must be associative.

    returns

      The result of applying reduce operator `op` between all the elements if the collection is nonempty.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Definition Classes
      TraversableOnce

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

    Optionally applies a binary operator to all elements of this collection, going left to right.

    Optionally applies a binary operator to all elements of this collection, 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)` is this collection is nonempty, `None` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

89. #### def reduceOption [A1 >: A] (op: (A1, A1) ⇒ A1): Option[A1]

    Optionally reduces the elements of this sequence using the specified associative binary operator.

    Optionally reduces the elements of this sequence using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    Note this method has a different signature than the `reduceLeftOption` and `reduceRightOption` methods of the trait `Traversable`. The result of reducing may only be a supertype of this parallel collection's type parameter `T`.

    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
      TraversableOnce → GenTraversableOnce

90. #### def reduceRight [B >: A] (op: (A, B) ⇒ B): B

    Applies a binary operator to all elements of this collection, going right to left.

    Applies a binary operator to all elements of this 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.

    B

      the result type of the binary operator.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this 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 collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

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

    Optionally applies a binary operator to all elements of this collection, going right to left.

    Optionally applies a binary operator to all elements of this 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.

    B

      the result type of the binary operator.

    op

      the binary operator.

    returns

      an option value containing the result of `reduceRight(op)` is this collection is nonempty, `None` otherwise.

    Definition Classes
      TraversableOnce → GenTraversableOnce

92. #### def repr : Traversable[A]

    The collection of type collection underlying this `TraversableLike` object.

    The collection of type collection underlying this `TraversableLike` object. By default this is implemented as the `TraversableLike` object itself, but this can be overridden.

    Definition Classes
      TraversableLike → GenTraversableLike

93. #### def reversed : List[A]

    Attributes
      protected[this]
    Definition Classes
      TraversableOnce

94. #### def scan [B >: A, That] (z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Traversable[A], B, That]): That

    Computes a prefix scan of the elements of the collection.

    Computes a prefix scan of the elements of the collection.

    Note: The neutral element `z` may be applied more than once.

    B

      element type of the resulting collection

    That

      type of the resulting collection

    z

      neutral element for the operator `op`

    op

      the associative operator for the scan

    cbf

      combiner factory which provides a combiner

    returns

      a new collection containing the prefix scan of the elements in this collection

    Definition Classes
      TraversableLike → GenTraversableLike

95. #### def scanLeft [B, That] (z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

    Produces a collection containing cummulative results of applying the operator going left to right.

    Produces a collection containing cummulative results of applying the operator going left to right.

    Note: will not terminate for infinite-sized collections.

    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

    That

      the actual type of the resulting collection

    z

      the initial value

    op

      the binary operator applied to the intermediate result and the element

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      collection with intermediate results

    Definition Classes
      TraversableLike → GenTraversableLike

96. #### def scanRight [B, That] (z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[Traversable[A], B, That]): That

    Produces a collection containing cummulative results of applying the operator going right to left.

    Produces a collection containing cummulative results of applying the operator going right to left. The head of the collection is the last cummulative result.

    Note: 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)

    B

      the type of the elements in the resulting collection

    That

      the actual type of the resulting collection

    z

      the initial value

    op

      the binary operator applied to the intermediate result and the element

    bf

      an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and and the new element type `B`.

    returns

      collection with intermediate results

    Definition Classes
      TraversableLike → GenTraversableLike
    Annotations
      @migration
    Migration

      "This scanRight definition has changed in 2.9.\n" + "The previous behavior can be reproduced with scanRight.reverse."

97. #### def seq : Traversable[A]

    A version of this collection with all of the operations implemented sequentially (i.

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

    This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.

    returns

      a sequential view of the collection.

    Definition Classes
      Traversable → Traversable → GenTraversable → Parallelizable → TraversableOnce → GenTraversableOnce

98. #### def size : Int

    The size of this collection.

    The size of this collection.

    Note: will not terminate for infinite-sized collections.

    returns

      the number of elements in this collection.

    Definition Classes
      TraversableOnce → GenTraversableOnce

99. #### def slice (from: Int, until: Int): Traversable[A]

    Selects an interval of elements.

    Selects an interval of elements. The returned collection is made up of all elements `x` which satisfy the invariant:

           from <= indexOf(x) < until

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

    from

      the lowest index to include from this collection.

    until

      the highest index to EXCLUDE from this collection.

    returns

      a collection containing the elements greater than or equal to index `from` extending up to (but not including) index `until` of this collection.

    Definition Classes
      TraversableLike → GenTraversableLike

100. #### def span (p: (A) ⇒ Boolean): (Traversable[A], Traversable[A])

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

     Splits this 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.

     p

       the test predicate

     returns

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

     Definition Classes
       TraversableLike → GenTraversableLike

101. #### def splitAt (n: Int): (Traversable[A], Traversable[A])

     Splits this collection into two at a given position.

     Splits this 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.

     n

       the position at which to split.

     returns

       a pair of collections consisting of the first `n` elements of this collection, and the other elements.

     Definition Classes
       TraversableLike → GenTraversableLike

102. #### def stringPrefix : String

     Defines the prefix of this object's `toString` representation.

     Defines the prefix of this object's `toString` representation.

     returns

       a string representation which starts the result of `toString` applied to this collection. By default the string prefix is the simple name of the collection class collection.

     Definition Classes
       TraversableLike → GenTraversableLike

103. #### 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 of this collection with respect to the `+` operator in `num`.

     Attributes
       abstract
     Definition Classes
       GenTraversableOnce

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

     Sums up the elements of this collection.

     Sums up the elements of this collection.

     B

       the result type of the `+` operator.

     num

       an implicit parameter defining a set of numeric operations which includes the `+` operator to be used in forming the sum.

     returns

       the sum of all elements of this collection with respect to the `+` operator in `num`.

     Definition Classes
       TraversableOnce → GenTraversableOnce

105. #### def synchronized [T0] (arg0: ⇒ T0): T0

     Attributes
       final
     Definition Classes
       AnyRef

106. #### def tail : Traversable[A]

     Selects all elements except the first.

     Selects all elements except the first.

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

     returns

       a collection consisting of all elements of this collection except the first one.

     Definition Classes
       TraversableLike → GenTraversableLike

107. #### def tails : Iterator[Traversable[A]]

     Iterates over the tails of this collection.

     Iterates over the tails of this collection. The first value will be this collection and the final one will be an empty collection, with the intervening values the results of successive applications of `tail`.

     returns

       an iterator over all the tails of this collection

     Definition Classes
       TraversableLike
     Example:

     1. `List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)`

108. #### def take (n: Int): Traversable[A]

     Selects first n elements.

     Selects first n elements.

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

     n

       Tt number of elements to take from this collection.

     returns

       a collection consisting only of the first `n` elements of this collection, or else the whole collection, if it has less than `n` elements.

     Definition Classes
       TraversableLike → GenTraversableLike

109. #### def takeWhile (p: (A) ⇒ Boolean): Traversable[A]

     Takes longest prefix of elements that satisfy a predicate.

     Takes longest prefix of elements that satisfy a predicate.

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

     p

       The predicate used to test elements.

     returns

       the longest prefix of this collection whose elements all satisfy the predicate `p`.

     Definition Classes
       TraversableLike → GenTraversableLike

110. #### def thisCollection : Traversable[A]

     The underlying collection seen as an instance of `CC`.

     The underlying collection seen as an instance of `CC`. By default this is implemented as the current collection object itself, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       TraversableLike

111. #### def toArray : Array[A]

     [use case] Converts this collection to an array.

     [use case]

     Converts this collection to an array.

     Note: will not terminate for infinite-sized collections.

     returns

       an array containing all elements of this collection.

     Attributes
       abstract
     Definition Classes
       GenTraversableOnce

112. #### def toArray [B >: A] (implicit arg0: ClassManifest[B]): Array[B]

     Converts this collection to an array.

     Converts this collection to an array.

     Note: will not terminate for infinite-sized collections.

     B

       the type of the elements of the array. A `ClassManifest` for this type must be available.

     returns

       an array containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

113. #### def toBuffer [B >: A] : Buffer[B]

     Converts this collection to a mutable buffer.

     Converts this collection to a mutable buffer.

     Note: will not terminate for infinite-sized collections.

     returns

       a buffer containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

114. #### def toCollection (repr: Traversable[A]): Traversable[A]

     A conversion from collections of type `Repr` to `CC` objects.

     A conversion from collections of type `Repr` to `CC` objects. By default this is implemented as just a cast, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       TraversableLike

115. #### def toIndexedSeq [B >: A] : IndexedSeq[B]

     Converts this collection to an indexed sequence.

     Converts this collection to an indexed sequence.

     Note: will not terminate for infinite-sized collections.

     returns

       an indexed sequence containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

116. #### def toIterable : Iterable[A]

     Converts this collection to an iterable collection.

     Converts this collection 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 collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

117. #### def toIterator : Iterator[A]

     Returns an Iterator over the elements in this collection.

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

     Note: will not terminate for infinite-sized collections.

     returns

       an Iterator containing all elements of this collection.

     Definition Classes
       TraversableLike → GenTraversableOnce

118. #### def toList : List[A]

     Converts this collection to a list.

     Converts this collection to a list.

     Note: will not terminate for infinite-sized collections.

     returns

       a list containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

119. #### def toMap [T, U] : Map[T, U]

     [use case] Converts this collection to a map.

     [use case]

     Converts this collection 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-sized collections.

     returns

       a map containing all elements of this collection.

     Attributes
       abstract
     Definition Classes
       GenTraversableOnce

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

     Converts this collection to a map.

     Converts this collection 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-sized collections.

     returns

       a map containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

121. #### def toSeq : Seq[A]

     Converts this collection to a sequence.

     Converts this collection 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 collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

122. #### def toSet [B >: A] : Set[B]

     Converts this collection to a set.

     Converts this collection to a set.

     Note: will not terminate for infinite-sized collections.

     returns

       a set containing all elements of this collection.

     Definition Classes
       TraversableOnce → GenTraversableOnce

123. #### def toStream : Stream[A]

     Converts this collection to a stream.

     Converts this collection to a stream.

     Note: will not terminate for infinite-sized collections.

     returns

       a stream containing all elements of this collection.

     Definition Classes
       TraversableLike → GenTraversableOnce

124. #### def toString (): String

     Converts this collection to a string.

     Converts this collection to a string.

     returns

       a string representation of this collection. By default this string consists of the `stringPrefix` of this collection, followed by all elements separated by commas and enclosed in parentheses.

     Definition Classes
       TraversableLike → AnyRef → Any

125. #### def toTraversable : Traversable[A]

     Converts this collection to an unspecified Traversable.

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

     Note: will not terminate for infinite-sized collections.

     returns

       a Traversable containing all elements of this collection.

     Definition Classes
       TraversableLike → TraversableOnce → GenTraversableOnce

126. #### def transpose [B] (implicit asTraversable: (A) ⇒ TraversableOnce[B]): Traversable[Traversable[B]]

     Transposes this collection of traversable collections into a collection of collections.

     Transposes this collection of traversable collections into a collection of collections.

     B

       the type of the elements of each traversable collection.

     asTraversable

       an implicit conversion which asserts that the element type of this collection is a `Traversable`.

     returns

       a two-dimensional collection of collections which has as nth row the nth column of this collection.

     Definition Classes
       Traversable → GenericTraversableTemplate
     Annotations
       @bridge()

127. #### def unzip [A1, A2] (implicit asPair: (A) ⇒ (A1, A2)): (Traversable[A1], Traversable[A2])

     Converts this collection of pairs into two collections of the first and second half of each pair.

     Converts this collection of pairs into two collections of the first and second half of each pair.

     asPair

       an implicit conversion which asserts that the element type of this collection is a pair.

     returns

       a pair collections, containing the first, respectively second half of each element pair of this collection.

     Definition Classes
       GenericTraversableTemplate

128. #### def unzip3 [A1, A2, A3] (implicit asTriple: (A) ⇒ (A1, A2, A3)): (Traversable[A1], Traversable[A2], Traversable[A3])

     Converts this collection of triples into three collections of the first, second, and third element of each triple.

     Converts this collection of triples into three collections of the first, second, and third element of each triple.

     returns

       a triple collections, containing the first, second, respectively third member of each element triple of this collection.

     Definition Classes
       GenericTraversableTemplate

129. #### def view (from: Int, until: Int): TraversableView[A, Traversable[A]]

     Creates a non-strict view of a slice of this collection.

     Creates a non-strict view of a slice of this collection.

     Note: the difference between `view` and `slice` is that `view` produces a view of the current collection, whereas `slice` produces a new 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.

     from

       the index of the first element of the view

     until

       the index of the element following the view

     returns

       a non-strict view of a slice of this collection, starting at index `from` and extending up to (but not including) index `until`.

     Definition Classes
       TraversableLike

130. #### def view : TraversableView[A, Traversable[A]]

     Creates a non-strict view of this collection.

     Creates a non-strict view of this collection.

     returns

       a non-strict view of this collection.

     Definition Classes
       TraversableLike

131. #### def wait (): Unit

     Attributes
       final
     Definition Classes
       AnyRef
     Annotations
       @throws()

132. #### def wait (arg0: Long, arg1: Int): Unit

     Attributes
       final
     Definition Classes
       AnyRef
     Annotations
       @throws()

133. #### def wait (arg0: Long): Unit

     Attributes
       final
     Definition Classes
       AnyRef
     Annotations
       @throws()

134. #### def withFilter (p: (A) ⇒ Boolean): FilterMonadic[A, Traversable[A]]

     Creates a non-strict filter of this collection.

     Creates a non-strict filter of this 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.

     p

       the predicate used to test elements.

     returns

       an object of class `WithFilter`, which supports `map`, `flatMap`, `foreach`, and `withFilter` operations. All these operations apply to those elements of this collection which satisfy the predicate `p`.

     Definition Classes
       TraversableLike → FilterMonadic

### Inherited from Mutable

### Inherited from Traversable[A]

### Inherited from GenTraversable[A]

### Inherited from GenericTraversableTemplate[A, Traversable]

### Inherited from TraversableLike[A, Traversable[A]]

### Inherited from GenTraversableLike[A, Traversable[A]]

### Inherited from Parallelizable[A, ParIterable[A]]

### Inherited from TraversableOnce[A]

### Inherited from GenTraversableOnce[A]

### Inherited from FilterMonadic[A, Traversable[A]]

### Inherited from HasNewBuilder[A, Traversable[A]]

### Inherited from AnyRef

### Inherited from Any