scala.collection

GenTraversableLike

trait GenTraversableLike[+A, +Repr] extends GenTraversableOnce[A] with Parallelizable[A, ParIterable[A]]

A template trait for all traversable collections upon which operations may be implemented in parallel.

Source
GenTraversableLike.scala
Linear Supertypes
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Abstract Value Members

  1. abstract def ++[B >: A, That](that: GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That

    Returns a new general collection containing the elements from the left hand operand followed by the elements from the right hand operand.

    Returns a new general collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the general collection is the most specific superclass encompassing the element types of the two operands (see example).

    Example:

        scala> val a = LinkedList(1)
        a: scala.collection.mutable.LinkedList[Int] = LinkedList(1)
    
        scala> val b = LinkedList(2)
        b: scala.collection.mutable.LinkedList[Int] = LinkedList(2)
    
        scala> val c = a ++ b
        c: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
    
        scala> val d = LinkedList('a')
        d: scala.collection.mutable.LinkedList[Char] = LinkedList(a)
    
        scala> val e = c ++ d
        e: scala.collection.mutable.LinkedList[AnyVal] = LinkedList(1, 2, a)
    
    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 general collection followed by all elements of that.

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

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

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

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

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
    
         scala> val b = (5 /: a)(_+_)
         b: Int = 15
    
         scala> val c = (5 /: a)((x,y) => x + y)
         c: Int = 15
    

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this general collection, going left to right with the start value z on the left:

                op(...op(op(z, x1), x2), ..., xn)
    

    where x1, ..., xn are the elements of this general collection.

    Definition Classes
    GenTraversableOnce
  3. abstract def :\[B](z: B)(op: (A, B) ⇒ B): B

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

    Applies a binary operator to all elements of this general 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.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
    
         scala> val b = (a :\ 5)(_+_)
         b: Int = 15
    
         scala> val c = (a :\ 5)((x,y) => x + y)
         c: Int = 15
    
    
    B

    the result type of the binary operator.

    z

    the start value

    op

    the binary operator

    returns

    the result of inserting op between consecutive elements of this general collection, going right to left with the start value z on the right:

                op(x1, op(x2, ... op(xn, z)...))
    

    where x1, ..., xn are the elements of this general collection.

    Definition Classes
    GenTraversableOnce
  4. abstract 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 an 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).

    B

    the type of accumulated results

    z

    the initial value for the accumulated result of the partition - this will typically be the neutral element for the seqop operator (e.g. Nil for list concatenation or 0 for summation)

    seqop

    an operator used to accumulate results within a partition

    combop

    an associative operator used to combine results from different partitions

    Definition Classes
    GenTraversableOnce
  5. abstract def collect[B, That](pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[Repr, B, That]): That

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

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

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

    Definition Classes
    GenTraversableOnce
  7. abstract def copyToArray[B >: A](xs: Array[B], start: Int): Unit

    Copies values of this general collection to an array.

    Copies values of this general collection to an array. Fills the given array xs with values of this general collection, beginning at index start. Copying will stop once either the end of the current general 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
    GenTraversableOnce
  8. abstract def copyToArray[B >: A](xs: Array[B]): Unit

    Copies values of this general collection to an array.

    Copies values of this general collection to an array. Fills the given array xs with values of this general collection. Copying will stop once either the end of the current general 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
    GenTraversableOnce
  9. abstract def count(p: (A) ⇒ Boolean): Int

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

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

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    GenTraversableOnce
  10. abstract def drop(n: Int): Repr

    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 general collection.

    returns

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

  11. abstract def dropWhile(pred: (A) ⇒ Boolean): Repr

    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.

    returns

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

  12. abstract def exists(pred: (A) ⇒ Boolean): Boolean

    Definition Classes
    GenTraversableOnce
  13. abstract def filter(pred: (A) ⇒ Boolean): Repr

    Selects all elements of this general collection which satisfy a predicate.

    Selects all elements of this general collection which satisfy a predicate.

    returns

    a new general collection consisting of all elements of this general collection that satisfy the given predicate p. Their order may not be preserved.

  14. abstract def filterNot(pred: (A) ⇒ Boolean): Repr

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

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

    returns

    a new general collection consisting of all elements of this general collection that do not satisfy the given predicate p. Their order may not be preserved.

  15. abstract def find(pred: (A) ⇒ Boolean): Option[A]

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

    Finds the first element of the general 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.

    returns

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

    Definition Classes
    GenTraversableOnce
  16. abstract def flatMap[B, That](f: (A) ⇒ GenTraversableOnce[B])(implicit bf: CanBuildFrom[Repr, B, That]): That

    Builds a new collection by applying a function to all elements of this general collection and using the elements of the resulting collections.

    Builds a new collection by applying a function to all elements of this general collection and using the elements of the resulting collections. For example:

     def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")
    

    The type of the resulting collection is guided by the static type of general collection. This might cause unexpected results sometimes. For example:

     // lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
     def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)
    
     // lettersOf will return a Set[Char], not a Seq
     def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq)
    
     // xs will be a an Iterable[Int]
     val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)
    
     // ys will be a Map[Int, Int]
     val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
    
    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 general collection and concatenating the results.

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

    Folds the elements of this general collection using the specified associative binary operator.

    Folds the elements of this general collection using the specified associative binary operator.

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

    A1

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

    z

    a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., Nil for list concatenation, 0 for addition, or 1 for multiplication.)

    op

    a binary operator that must be associative

    returns

    the result of applying fold operator op between all the elements and z

    Definition Classes
    GenTraversableOnce
  18. abstract def foldLeft[B](z: B)(op: (B, A) ⇒ B): B

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

    Applies a binary operator to a start value and all elements of this general 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 general collection, going left to right with the start value z on the left:

                op(...op(z, x1), x2, ..., xn)
    

    where x1, ..., xn are the elements of this general collection.

    Definition Classes
    GenTraversableOnce
  19. abstract def foldRight[B](z: B)(op: (A, B) ⇒ B): B

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

    Applies a binary operator to all elements of this general 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 general collection, going right to left with the start value z on the right:

                op(x1, op(x2, ... op(xn, z)...))
    

    where x1, ..., xn are the elements of this general collection.

    Definition Classes
    GenTraversableOnce
  20. abstract def forall(pred: (A) ⇒ Boolean): Boolean

    Definition Classes
    GenTraversableOnce
  21. abstract def foreach[U](f: (A) ⇒ U): Unit

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

    Applies a function f to all elements of this general 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.

    Definition Classes
    GenTraversableLikeGenTraversableOnce
  22. abstract def groupBy[K](f: (A) ⇒ K): GenMap[K, Repr]

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

    Partitions this general collection into a map of general 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 general collection.

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

    A map from keys to general 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 general collection of those elements x for which f(x) equals k.

  23. abstract def hasDefiniteSize: Boolean

    Definition Classes
    GenTraversableOnce
  24. abstract def head: A

  25. abstract def isEmpty: Boolean

    Tests whether the general collection is empty.

    Tests whether the general collection is empty.

    returns

    true if the general collection contains no elements, false otherwise.

    Definition Classes
    GenTraversableOnce
  26. abstract def map[B, That](f: (A) ⇒ B)(implicit bf: CanBuildFrom[Repr, B, That]): That

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

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

  27. abstract def max[A1 >: A](implicit ord: Ordering[A1]): A

    Finds the largest element.

    Finds the largest element.

    returns

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

    Definition Classes
    GenTraversableOnce
  28. abstract def maxBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Definition Classes
    GenTraversableOnce
  29. abstract def min[A1 >: A](implicit ord: Ordering[A1]): A

    Finds the smallest element.

    Finds the smallest element.

    returns

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

    Definition Classes
    GenTraversableOnce
  30. abstract def minBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

    Definition Classes
    GenTraversableOnce
  31. abstract def mkString: String

    Displays all elements of this general collection in a string.

    Displays all elements of this general collection in a string.

    returns

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

    Definition Classes
    GenTraversableOnce
  32. abstract def mkString(sep: String): String

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

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

    sep

    the separator string.

    returns

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

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

  33. abstract def mkString(start: String, sep: String, end: String): String

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

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

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

  34. abstract def nonEmpty: Boolean

    Tests whether the general collection is not empty.

    Tests whether the general collection is not empty.

    returns

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

    Definition Classes
    GenTraversableOnce
  35. abstract 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
    Parallelizable
  36. abstract def partition(pred: (A) ⇒ Boolean): (Repr, Repr)

    Partitions this general collection in two general collections according to a predicate.

    Partitions this general collection in two general collections according to a predicate.

    returns

    a pair of general collections: the first general collection consists of all elements that satisfy the predicate p and the second general collection consists of all elements that don't. The relative order of the elements in the resulting general collections may not be preserved.

  37. abstract def product[A1 >: A](implicit num: Numeric[A1]): A1

    Multiplies up the elements of this collection.

    Multiplies up the elements of this collection.

    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 general collection with respect to the * operator in num.

    Definition Classes
    GenTraversableOnce
  38. abstract def reduce[A1 >: A](op: (A1, A1) ⇒ A1): A1

    Reduces the elements of this general collection using the specified associative binary operator.

    Reduces the elements of this general collection using the specified associative binary operator.

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

    A1

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

    op

    A binary operator that must be associative.

    returns

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

    Definition Classes
    GenTraversableOnce
    Exceptions thrown
    UnsupportedOperationException

    if this general collection is empty.

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

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

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

    Definition Classes
    GenTraversableOnce
  40. abstract def reduceOption[A1 >: A](op: (A1, A1) ⇒ A1): Option[A1]

    Reduces the elements of this general collection, if any, using the specified associative binary operator.

    Reduces the elements of this general collection, if any, using the specified associative binary operator.

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

    A1

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

    op

    A binary operator that must be associative.

    returns

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

    Definition Classes
    GenTraversableOnce
  41. abstract def reduceRight[B >: A](op: (A, B) ⇒ B): B

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

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

                op(x,,1,,, op(x,,2,,, ..., op(x,,n-1,,, x,,n,,)...))
    

    where x1, ..., xn are the elements of this general collection.

    Definition Classes
    GenTraversableOnce
    Exceptions thrown
    `UnsupportedOperationException`

    if this general collection is empty.

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

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

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

    Definition Classes
    GenTraversableOnce
  43. abstract def repr: Repr

  44. abstract def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Repr, 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 general collection containing the prefix scan of the elements in this general collection

  45. abstract def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[Repr, 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

  46. abstract def scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[Repr, 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

    Annotations
    @migration
    Migration

    (Changed in version 2.9.0) The behavior of scanRight has changed. The previous behavior can be reproduced with scanRight.reverse.

  47. abstract def seq: TraversableOnce[A]

    Definition Classes
    Parallelizable
  48. abstract def size: Int

    The size of this general collection.

    The size of this general collection.

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this general collection.

    Definition Classes
    GenTraversableLikeGenTraversableOnce
  49. abstract def slice(unc_from: Int, unc_until: Int): Repr

    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.

    returns

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

  50. abstract def span(pred: (A) ⇒ Boolean): (Repr, Repr)

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

    Splits this general 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.

    returns

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

  51. abstract def splitAt(n: Int): (Repr, Repr)

    Splits this general collection into two at a given position.

    Splits this general 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 general collections consisting of the first n elements of this general collection, and the other elements.

  52. abstract 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 general collection. By default the string prefix is the simple name of the collection class general collection.

  53. abstract def sum[A1 >: A](implicit num: Numeric[A1]): A1

    Sums up the elements of this collection.

    Sums up the elements of this collection.

    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 general collection with respect to the + operator in num.

    Definition Classes
    GenTraversableOnce
  54. abstract def take(n: Int): Repr

    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 general collection.

    returns

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

  55. abstract def takeWhile(pred: (A) ⇒ Boolean): Repr

    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.

    returns

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

  56. abstract def toArray[A1 >: A](implicit arg0: ClassManifest[A1]): Array[A1]

    Converts this general collection to an array.

    Converts this general collection to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  57. abstract def toBuffer[A1 >: A]: Buffer[A1]

    Converts this general collection to a mutable buffer.

    Converts this general collection to a mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  58. abstract def toIndexedSeq[A1 >: A]: IndexedSeq[A1]

    Converts this general collection to an indexed sequence.

    Converts this general collection to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

    an indexed sequence containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  59. abstract def toIterable: GenIterable[A]

    Converts this general collection to an iterable collection.

    Converts this general 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 general collection.

    Definition Classes
    GenTraversableOnce
  60. abstract def toIterator: Iterator[A]

    Returns an Iterator over the elements in this general collection.

    Returns an Iterator over the elements in this general 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 general collection.

    Definition Classes
    GenTraversableOnce
  61. abstract def toList: List[A]

    Converts this general collection to a list.

    Converts this general collection to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  62. abstract def toMap[K, V](implicit ev: <:<[A, (K, V)]): GenMap[K, V]

    Converts this general collection to a map.

    Converts this general 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 general collection.

    Definition Classes
    GenTraversableOnce
  63. abstract def toSeq: GenSeq[A]

    Converts this general collection to a sequence.

    Converts this general 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 general collection.

    Definition Classes
    GenTraversableOnce
  64. abstract def toSet[A1 >: A]: GenSet[A1]

    Converts this general collection to a set.

    Converts this general collection to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  65. abstract def toStream: Stream[A]

    Converts this general collection to a stream.

    Converts this general collection to a stream.

    Note: will not terminate for infinite-sized collections.

    returns

    a stream containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  66. abstract def toTraversable: GenTraversable[A]

    Converts this general collection to an unspecified Traversable.

    Converts this general 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 general collection.

    Definition Classes
    GenTraversableOnce

Concrete Value Members

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

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

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

    Definition Classes
    Any
  3. final 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 ==

    Definition Classes
    AnyRef → Any
  4. abstract def ++[B](that: GenTraversableOnce[B]): GenTraversable[B]

    [use case] Returns a new general collection containing the elements from the left hand operand followed by the elements from the right hand operand.

    [use case]

    Returns a new general collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the general collection is the most specific superclass encompassing the element types of the two operands (see example).

    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 general collection followed by all elements of that.

  5. 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.

    Example:

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
    
         scala> val b = (a /:\ 5)(_+_)
         b: Int = 15
    
    Definition Classes
    GenTraversableOnce
  6. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  7. final 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.

    Definition Classes
    Any
  8. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

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

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown
    ClassCastException

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

  9. 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()
    Note

    not specified by SLS as a member of AnyRef

  10. abstract def collect[B](pf: PartialFunction[A, B]): GenTraversable[B]

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

    [use case]

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

    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the general 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.

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

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

    [use case]

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

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    GenTraversableOnce
  12. abstract def copyToArray(xs: Array[A]): Unit

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

    [use case]

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

    xs

    the array to fill.

    Definition Classes
    GenTraversableOnce
  13. final 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.

    Definition Classes
    AnyRef
  14. 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
  15. 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()
    Note

    not specified by SLS as a member of AnyRef

  16. abstract def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): GenTraversable[B]

    [use case] Builds a new collection by applying a function to all elements of this general collection and using the elements of the resulting collections.

    [use case]

    Builds a new collection by applying a function to all elements of this general collection and using the elements of the resulting collections. For example:

    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 general collection and concatenating the results.

  17. abstract def foreach(f: (A) ⇒ Unit): Unit

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

    [use case]

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

    f

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

  18. final 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.

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  19. 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
  20. final def isInstanceOf[T0]: Boolean

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

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

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

    returns

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

    Definition Classes
    Any
  21. final def isTraversableAgain: Boolean

    Tests whether this general collection can be repeatedly traversed.

    Tests whether this general collection can be repeatedly traversed.

    returns

    true

    Definition Classes
    GenTraversableLikeGenTraversableOnce
  22. abstract def map[B](f: (A) ⇒ B): GenTraversable[B]

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

    [use case]

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

  23. abstract def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

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

    Definition Classes
    GenTraversableOnce
  24. abstract def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

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

    Definition Classes
    GenTraversableOnce
  25. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

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

    Definition Classes
    AnyRef
  26. final def notify(): Unit

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

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

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  27. final def notifyAll(): Unit

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

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

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  28. 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
  29. abstract 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 general collection with respect to the * operator in num.

    Definition Classes
    GenTraversableOnce
  30. abstract 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 general collection with respect to the + operator in num.

    Definition Classes
    GenTraversableOnce
  31. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  32. def tail: Repr

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

    Exceptions thrown
    `UnsupportedOperationException`

    if the general collection is empty.

  33. abstract def toArray: Array[A]

    [use case] Converts this general collection to an array.

    [use case]

    Converts this general collection to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this general collection.

    Definition Classes
    GenTraversableOnce
  34. abstract def toMap[T, U]: Map[T, U]

    [use case] Converts this general collection to a map.

    [use case]

    Converts this general 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 general collection.

    Definition Classes
    GenTraversableOnce
  35. def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

    a String representation of the object.

    Definition Classes
    AnyRef → Any
  36. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws()
  37. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws()
  38. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws()

Inherited from Parallelizable[A, ParIterable[A]]

Inherited from GenTraversableOnce[A]

Inherited from AnyRef

Inherited from Any