GenTraversable

trait GenTraversable[+A] extends GenTraversableLike[A, GenTraversable[A]] with GenTraversableOnce[A] with GenericTraversableTemplate[A, GenTraversable]

A trait for all traversable collections which may possibly have their operations implemented in parallel.

Source
GenTraversable.scala
Since

2.9

Linear Supertypes
GenericTraversableTemplate[A, GenTraversable], HasNewBuilder[A, scala.collection.GenTraversable[A] @scala.annotation.unchecked.uncheckedVariance], GenTraversableLike[A, GenTraversable[A]], Parallelizable[A, ParIterable[A]], GenTraversableOnce[A], AnyRef, Any
Ordering
1. Alphabetic
2. By inheritance
Inherited
1. GenTraversable
2. GenericTraversableTemplate
3. HasNewBuilder
4. GenTraversableLike
5. Parallelizable
6. GenTraversableOnce
7. AnyRef
8. Any
Implicitly
1. by traversable2ops
3. by any2stringfmt
4. by any2ArrowAssoc
5. by any2Ensuring
1. Hide All
2. Show all
Visibility
1. Public
2. All

Abstract Value Members

1. abstract 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`.

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)

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 collection, going left to right with the start value `z` on the left:

`op(...op(op(z, x_1), x_2), ..., x_n)`

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

Definition Classes
GenTraversableOnce
2. abstract 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.

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)

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 collection, going right to left with the start value `z` on the right:

`op(x_1, op(x_2, ... op(x_n, z)...))`

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

Definition Classes
GenTraversableOnce
3. 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
4. abstract def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Unit

Definition Classes
GenTraversableOnce
5. abstract 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
GenTraversableOnce
6. abstract def drop(n: Int): GenTraversable[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
GenTraversableLike
7. abstract def dropWhile(pred: (A) ⇒ Boolean): GenTraversable[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.

pred

The predicate used to test elements.

returns

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

Definition Classes
GenTraversableLike
8. abstract def exists(pred: (A) ⇒ Boolean): Boolean

Definition Classes
GenTraversableOnce
9. abstract def filter(pred: (A) ⇒ Boolean): GenTraversable[A]

Selects all elements of this collection which satisfy a predicate.

Selects all elements of this collection which satisfy a predicate.

pred

the predicate used to test elements.

returns

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

Definition Classes
GenTraversableLike
10. abstract def filterNot(pred: (A) ⇒ Boolean): GenTraversable[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.

pred

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`. Their order may not be preserved.

Definition Classes
GenTraversableLike
11. abstract def find(pred: (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.

pred

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

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

Folds the elements of this 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
13. abstract 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 `x1, ..., xn` are the elements of this collection.

Definition Classes
GenTraversableOnce
14. abstract 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 `x1, ..., xn` are the elements of this collection.

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

Definition Classes
GenTraversableOnce
16. abstract def groupBy[K](f: (A) ⇒ K): GenMap[K, GenTraversable[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
GenTraversableLike
17. abstract def hasDefiniteSize: Boolean

Definition Classes
GenTraversableOnce

Selects the first element of this collection.

Selects the first element of this collection.

returns

the first element of this collection.

Definition Classes
GenericTraversableTemplate
Exceptions thrown
`NoSuchElementException`

if the collection is empty.

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
GenTraversableLike
20. abstract def init: GenTraversable[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
GenTraversableLike
Exceptions thrown
`UnsupportedOperationException`

if the collection is empty.

21. abstract 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
GenericTraversableTemplate
22. abstract def isTraversableAgain: Boolean

Tests whether this collection can be repeatedly traversed.

Tests whether this collection can be repeatedly traversed.

returns

`true`

Definition Classes
GenTraversableLikeGenTraversableOnce
23. abstract 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
GenTraversableLike
Exceptions thrown
NoSuchElementException

If the collection is empty.

24. abstract 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
GenTraversableLike
25. abstract def maxBy[B](f: (A) ⇒ B)(implicit cmp: Ordering[B]): A

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

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

29. abstract 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
GenTraversableOnce
Example:
1. `List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"`

30. abstract 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
GenTraversableOnce
31. 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
32. abstract def partition(pred: (A) ⇒ Boolean): (GenTraversable[A], GenTraversable[A])

Partitions this collection in two collections according to a predicate.

Partitions this collection in two collections according to a predicate.

pred

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 may not be preserved.

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

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

Reduces the elements of this 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 collection is nonempty.

Definition Classes
GenTraversableOnce
Exceptions thrown
UnsupportedOperationException

if this collection is empty.

34. abstract 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
GenTraversableOnce
35. abstract def reduceOption[A1 >: A](op: (A1, A1) ⇒ A1): Option[A1]

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

Reduces the elements of this 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
36. abstract 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 `x1, ..., xn` are the elements of this collection.

Definition Classes
GenTraversableOnce
Exceptions thrown
`UnsupportedOperationException`

if this collection is empty.

37. abstract 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
GenTraversableOnce
38. abstract def repr: GenTraversable[A]

Definition Classes
GenTraversableLike
39. abstract def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[GenTraversable[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
GenTraversableLike
40. abstract def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[GenTraversable[A], B, That]): That

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

Produces a collection containing cumulative 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
GenTraversableLike
41. abstract def scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[GenTraversable[A], B, That]): That

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

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

Note: will not terminate for infinite-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
GenTraversableLike
Annotations
@migration
Migration

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

43. abstract 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
GenTraversableLikeGenTraversableOnce
44. abstract def slice(unc_from: Int, unc_until: Int): GenTraversable[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.

unc_from

the lowest index to include from this collection.

unc_until

the lowest 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
GenTraversableLike
45. abstract def span(pred: (A) ⇒ Boolean): (GenTraversable[A], GenTraversable[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.

pred

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
GenTraversableLike
46. abstract def splitAt(n: Int): (GenTraversable[A], GenTraversable[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
GenTraversableLike
47. 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 collection. By default the string prefix is the simple name of the collection class collection.

Definition Classes
GenTraversableLike
48. abstract def tail: GenTraversable[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
GenTraversableLike
Exceptions thrown
`UnsupportedOperationException`

if the collection is empty.

49. abstract def take(n: Int): GenTraversable[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

the 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
GenTraversableLike
50. abstract def takeWhile(pred: (A) ⇒ Boolean): GenTraversable[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.

pred

The predicate used to test elements.

returns

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

Definition Classes
GenTraversableLike
51. abstract def toBuffer[A1 >: A]: Buffer[A1]

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
GenTraversableOnce
52. abstract def toIndexedSeq: immutable.IndexedSeq[A]

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
GenTraversableOnce
53. abstract def toIterable: GenIterable[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
GenTraversableOnce
54. abstract 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
GenTraversableOnce
55. abstract 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
GenTraversableOnce
56. abstract def toSeq: GenSeq[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
GenTraversableOnce
57. abstract def toSet[A1 >: A]: GenSet[A1]

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
GenTraversableOnce
58. abstract 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
GenTraversableOnce
59. abstract def toTraversable: GenTraversable[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
GenTraversableOnce
60. abstract def toVector: Vector[A]

Converts this collection to a Vector.

Converts this collection to a Vector.

Note: will not terminate for infinite-sized collections.

returns

a vector containing all elements of this 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 and `null`.

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

returns

a hash value consistent with ==

Definition Classes
AnyRef → Any
4. def +(other: String): String

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to StringAdd performed by method any2stringadd in scala.Predef.
Definition Classes
5. abstract def ++[B](that: GenTraversableOnce[B]): CC[B]

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

[use case]

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

Example:

```scala> val a = LinkedList(1)

scala> val c = a ++ b

scala> val e = c ++ d
B

the element type of the returned collection.

that

the traversable to append.

returns

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

Definition Classes
GenTraversableLike
Full Signature

6. def ->[B](y: B): (GenTraversable[A], B)

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to ArrowAssoc[GenTraversable[A]] performed by method any2ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
()
7. final def ==(arg0: AnyRef): Boolean

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

Test two objects for equality.

Test two objects for equality. The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

returns

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

Definition Classes
Any
9. 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

Definition Classes
Any
Exceptions thrown
ClassCastException

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

10. def asParIterable: ParIterable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
11. def asParSeq: ParSeq[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
12. 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[java.lang]
Definition Classes
AnyRef
Annotations
( ... )
Note

not specified by SLS as a member of AnyRef

13. abstract 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 resulting from applying the given partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

Definition Classes
GenTraversableLike
Full Signature

14. def companion: GenericCompanion[GenTraversable]

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
GenTraversableGenericTraversableTemplate
15. abstract 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.

Note: will not terminate for infinite-sized collections.

xs

the array to fill.

start

the starting index.

Definition Classes
GenTraversableOnce
Full Signature

16. abstract 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.

Note: will not terminate for infinite-sized collections.

xs

the array to fill.

Definition Classes
GenTraversableOnce
Full Signature

17. def ensuring(cond: (GenTraversable[A]) ⇒ Boolean, msg: ⇒ Any): GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to Ensuring[GenTraversable[A]] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
18. def ensuring(cond: (GenTraversable[A]) ⇒ Boolean): GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to Ensuring[GenTraversable[A]] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
19. def ensuring(cond: Boolean, msg: ⇒ Any): GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to Ensuring[GenTraversable[A]] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
20. def ensuring(cond: Boolean): GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to Ensuring[GenTraversable[A]] performed by method any2Ensuring in scala.Predef.
Definition Classes
Ensuring
21. 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
22. def equals(arg0: Any): Boolean

The equality method for reference types.

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

See also `equals` in scala.Any.

returns

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

Definition Classes
AnyRef → Any
23. 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[java.lang]
Definition Classes
AnyRef
Annotations
( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

24. abstract 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 using the elements of the resulting collections.

[use case]

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

f

the function to apply to each element.

returns

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

Definition Classes
GenTraversableLike
Full Signature

25. def flatten[B]: CC[B]

[use case] Converts this collection of traversable collections into a collection formed by the elements of these traversable collections.

[use case]

Converts this collection of traversable collections into a collection formed by the elements of these traversable collections.

The resulting collection's type will be guided by the static type of collection. For example:

```val xs = List(Set(1, 2, 3), Set(1, 2, 3))
// xs == List(1, 2, 3, 1, 2, 3)

val ys = Set(List(1, 2, 3), List(3, 2, 1))
// ys == Set(1, 2, 3)```
B

the type of the elements of each traversable collection.

returns

a new collection resulting from concatenating all element collections.

Definition Classes
GenericTraversableTemplate
Full Signature

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

[use case]

[use case]
f

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

Definition Classes
GenericTraversableTemplate
Full Signature

27. def formatted(fmtstr: String): String

Returns string formatted according to given `format` string.

Returns string formatted according to given `format` string. Format strings are as for `String.format` (@see java.lang.String.format).

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to StringFormat performed by method any2stringfmt in scala.Predef.
Definition Classes
StringFormat
Annotations
()
28. def genericBuilder[B]: Builder[B, GenTraversable[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
29. final def getClass(): 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

30. def hashCode(): Int

The hashCode method for reference types.

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

returns

the hash code value for this object.

Definition Classes
AnyRef → Any
31. def ifParSeq[R](isbody: (ParSeq[A]) ⇒ R): (TraversableOps[A])#Otherwise[R]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
32. 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
33. def isParIterable: Boolean

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
34. def isParSeq: Boolean

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
35. def isParallel: Boolean

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
36. abstract 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 resulting from applying the given function `f` to each element of this collection and collecting the results.

Definition Classes
GenTraversableLike
Full Signature

37. abstract def max: A

[use case] Finds the largest element.

[use case]

Finds the largest element.

returns

the largest element of this collection.

Definition Classes
GenTraversableOnce
Full Signature

38. abstract def min: A

[use case] Finds the smallest element.

[use case]

Finds the smallest element.

returns

the smallest element of this collection

Definition Classes
GenTraversableOnce
Full Signature

39. 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
40. def newBuilder: Builder[A, GenTraversable[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
41. 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

42. 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

43. 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
44. 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 in this collection of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the collection and as result type of `product`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

Definition Classes
GenTraversableOnce
Full Signature

45. 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 in this collection of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the collection and as result type of `sum`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

Definition Classes
GenTraversableOnce
Full Signature

46. final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
47. abstract def to[Col[_]]: Col[A]

[use case] Converts this collection into another by copying all elements.

[use case]

Converts this collection into another by copying all elements.

Note: will not terminate for infinite-sized collections.

Col

The collection type to build.

returns

a new collection containing all elements of this collection.

Definition Classes
GenTraversableOnce
Full Signature

48. abstract 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. An `ClassTag` must be available for the element type of this collection.

Definition Classes
GenTraversableOnce
Full Signature

49. abstract 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 of type `immutable.Map[T, U]` containing all key/value pairs of type `(T, U)` of this collection.

Definition Classes
GenTraversableOnce
Full Signature

50. def toParArray: ParArray[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to TraversableOps[A] performed by method traversable2ops in scala.collection.parallel.
Definition Classes
TraversableOps
51. 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
52. def transpose[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): GenTraversable[GenTraversable[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
GenericTraversableTemplate
Annotations
@migration
Migration

(Changed in version 2.9.0) `transpose` throws an `IllegalArgumentException` if collections are not uniformly sized.

Exceptions thrown
`IllegalArgumentException`

if all collections in this collection are not of the same size.

53. def unzip[A1, A2](implicit asPair: (A) ⇒ (A1, A2)): (GenTraversable[A1], GenTraversable[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.

A1

the type of the first half of the element pairs

A2

the type of the second half of the element pairs

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
54. def unzip3[A1, A2, A3](implicit asTriple: (A) ⇒ (A1, A2, A3)): (GenTraversable[A1], GenTraversable[A2], GenTraversable[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.

A1

the type of the first member of the element triples

A2

the type of the second member of the element triples

A3

the type of the third member of the element triples

asTriple

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

returns

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

Definition Classes
GenericTraversableTemplate
55. final def wait(): Unit

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

Definition Classes
AnyRef
Annotations
( ... )
57. final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
( ... )
58. def →[B](y: B): (GenTraversable[A], B)

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to ArrowAssoc[GenTraversable[A]] performed by method any2ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

1. val self: Any

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to StringAdd performed by method any2stringadd in scala.Predef.
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
`(genTraversable: StringAdd).self`
Definition Classes
2. val self: Any

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to StringFormat performed by method any2stringfmt in scala.Predef.
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
`(genTraversable: StringFormat).self`
Definition Classes
StringFormat

Deprecated Value Members

1. 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)

scala> val b = (a /:\ 5)(_+_)
b: Int = 15```
Definition Classes
GenTraversableOnce
Annotations
Deprecated

(Since version 2.10.0) use fold instead

2. def x: GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to ArrowAssoc[GenTraversable[A]] performed by method any2ArrowAssoc in scala.Predef.
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
`(genTraversable: ArrowAssoc[GenTraversable[A]]).x`
Definition Classes
ArrowAssoc
Annotations
Deprecated

(Since version 2.10.0) Use `leftOfArrow instead`

3. def x: GenTraversable[A]

Implicit information
This member is added by an implicit conversion from GenTraversable[A] to Ensuring[GenTraversable[A]] performed by method any2Ensuring in scala.Predef.
This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
To access this member you can use a type ascription:
`(genTraversable: Ensuring[GenTraversable[A]]).x`
Definition Classes
Ensuring
Annotations
Deprecated

(Since version 2.10.0) Use `resultOfEnsuring instead`