scala.collection.immutable

Traversable

trait Traversable [+A] extends Traversable[A] with GenericTraversableTemplate[A, Traversable] with TraversableLike[A, Traversable[A]] with Immutable

A trait for traversable collections that are guaranteed immutable.

This is a base trait of all kinds of immutable 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
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  1. Traversable
  2. Immutable
  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
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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
    TraversableLikeGenTraversableLike
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableTraversableGenTraversableGenericTraversableTemplate
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLikeFilterMonadic
  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
    TraversableGenericTraversableTemplate
    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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    GenTraversableLikeGenTraversableOnce
  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
    TraversableLikeGenTraversableLikeFilterMonadic
  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
    TraversableOnceGenTraversableOnce
  69. def maxBy [B] (f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
    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
    TraversableOnceGenTraversableOnce
    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
    GenericTraversableTemplateHasNewBuilder
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeParallelizable
  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
    TraversableLikeGenTraversableLike
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
    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
    TraversableTraversableGenTraversableParallelizableTraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableLikeGenTraversableLike
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableOnceGenTraversableOnce
  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
    TraversableLikeGenTraversableOnce
  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
    TraversableLikeTraversableOnceGenTraversableOnce
  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
    TraversableGenericTraversableTemplate
    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
    TraversableLikeFilterMonadic

Inherited from Immutable

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