Packages

trait Seq[+A] extends Iterable[A] with collection.Seq[A] with GenericTraversableTemplate[A, Seq] with SeqLike[A, Seq[A]] with Parallelizable[A, ParSeq[A]]

A subtrait of collection.Seq which represents sequences that are guaranteed immutable.

Sequences are special cases of iterable collections of class Iterable. Unlike iterables, sequences always have a defined order of elements. Sequences provide a method apply for indexing. Indices range from 0 up to the length of a sequence. Sequences support a number of methods to find occurrences of elements or subsequences, including segmentLength, prefixLength, indexWhere, indexOf, lastIndexWhere, lastIndexOf, startsWith, endsWith, indexOfSlice.

Another way to see a sequence is as a PartialFunction from Int values to the element type of the sequence. The isDefinedAt method of a sequence returns true for the interval from 0 until length.

Sequences can be accessed in reverse order of their elements, using methods reverse and reverseIterator.

Sequences have two principal subtraits, IndexedSeq and LinearSeq, which give different guarantees for performance. An IndexedSeq provides fast random-access of elements and a fast length operation. A LinearSeq provides fast access only to the first element via head, but also has a fast tail operation.

Source
Seq.scala
Linear Supertypes
collection.Seq[A], SeqLike[A, Seq[A]], GenSeq[A], GenSeqLike[A, Seq[A]], PartialFunction[Int, A], (Int) ⇒ A, Iterable[A], collection.Iterable[A], IterableLike[A, Seq[A]], Equals, GenIterable[A], GenIterableLike[A, Seq[A]], Traversable[A], Immutable, collection.Traversable[A], GenTraversable[A], GenericTraversableTemplate[A, Seq], TraversableLike[A, Seq[A]], GenTraversableLike[A, Seq[A]], Parallelizable[A, ParSeq[A]], TraversableOnce[A], GenTraversableOnce[A], FilterMonadic[A, Seq[A]], HasNewBuilder[A, scala.collection.immutable.Seq[A] @scala.annotation.unchecked.uncheckedVariance], AnyRef, Any
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Inherited
  1. Seq
  2. Seq
  3. SeqLike
  4. GenSeq
  5. GenSeqLike
  6. PartialFunction
  7. Function1
  8. Iterable
  9. Iterable
  10. IterableLike
  11. Equals
  12. GenIterable
  13. GenIterableLike
  14. Traversable
  15. Immutable
  16. Traversable
  17. GenTraversable
  18. GenericTraversableTemplate
  19. TraversableLike
  20. GenTraversableLike
  21. Parallelizable
  22. TraversableOnce
  23. GenTraversableOnce
  24. FilterMonadic
  25. HasNewBuilder
  26. AnyRef
  27. Any
Implicitly
  1. by CollectionsHaveToParArray
  2. by MonadOps
  3. by any2stringadd
  4. by StringFormat
  5. by Ensuring
  6. by ArrowAssoc
  7. by alternateImplicit
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Type Members

  1. class WithFilter extends FilterMonadic[A, Repr]

    A class supporting filtered operations.

    A class supporting filtered operations. Instances of this class are returned by method withFilter.

    Definition Classes
    TraversableLike

Abstract Value Members

  1. abstract def apply(idx: Int): A

    Selects an element by its index in the sequence.

    Selects an element by its index in the sequence.

    Example:

    scala> val x = List(1, 2, 3, 4, 5)
    x: List[Int] = List(1, 2, 3, 4, 5)
    
    scala> x(3)
    res1: Int = 4
    idx

    The index to select.

    returns

    the element of this sequence at index idx, where 0 indicates the first element.

    Definition Classes
    SeqLikeGenSeqLike
    Exceptions thrown

    IndexOutOfBoundsException if idx does not satisfy 0 <= idx < length.

  2. abstract def iterator: Iterator[A]

    Creates a new iterator over all elements contained in this iterable object.

    Creates a new iterator over all elements contained in this iterable object.

    returns

    the new iterator

    Definition Classes
    IterableLikeGenIterableLike
  3. abstract def length: Int

    The length of the sequence.

    The length of the sequence.

    Note: will not terminate for infinite-sized collections.

    Note: xs.length and xs.size yield the same result.

    returns

    the number of elements in this sequence.

    Definition Classes
    SeqLikeGenSeqLike
    Exceptions thrown

    IllegalArgumentException if the length of the sequence cannot be represented in an Int, for example, (-1 to Int.MaxValue).length.

Concrete Value Members

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

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

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

    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 the new element type B.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  2. def ++:[B >: A, That](that: collection.Traversable[B])(implicit bf: CanBuildFrom[Seq[A], B, That]): That

    As with ++, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    As with ++, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.

    Example:

    scala> val x = List(1)
    x: List[Int] = List(1)
    
    scala> val y = LinkedList(2)
    y: scala.collection.mutable.LinkedList[Int] = LinkedList(2)
    
    scala> val z = x ++: y
    z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

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

    Since TraversableOnce has no ++ method, we have to implement that directly, but Traversable and down can use the overload.

    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 the new element type B.

    returns

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

    Definition Classes
    TraversableLike
  3. def ++:[B](that: TraversableOnce[B]): Seq[B]

    [use case] As with ++, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    [use case]

    As with ++, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

    It differs from ++ in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.

    Example:

    scala> val x = List(1)
    x: List[Int] = List(1)
    
    scala> val y = LinkedList(2)
    y: scala.collection.mutable.LinkedList[Int] = LinkedList(2)
    
    scala> val z = x ++: y
    z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)
    B

    the element type of the returned collection.

    that

    the traversable to append.

    returns

    a new immutable sequence which contains all elements of this immutable sequence followed by all elements of that.

    Definition Classes
    TraversableLike
    Full Signature

    def ++:[B >: A, That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  4. def +:(elem: A): Seq[A]

    [use case] A copy of the immutable sequence with an element prepended.

    [use case]

    A copy of the immutable sequence with an element prepended.

    Note that :-ending operators are right associative (see example). A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

    Also, the original immutable sequence is not modified, so you will want to capture the result.

    Example:

    scala> val x = List(1)
    x: List[Int] = List(1)
    
    scala> val y = 2 +: x
    y: List[Int] = List(2, 1)
    
    scala> println(x)
    List(1)
    elem

    the prepended element

    returns

    a new immutable sequence consisting of elem followed by all elements of this immutable sequence.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def +:[B >: A, That](elem: B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  5. def :+(elem: A): Seq[A]

    [use case] A copy of this immutable sequence with an element appended.

    [use case]

    A copy of this immutable sequence with an element appended.

    A mnemonic for +: vs. :+ is: the COLon goes on the COLlection side.

    Note: will not terminate for infinite-sized collections.

    Example:

    scala> val a = List(1)
    a: List[Int] = List(1)
    
    scala> val b = a :+ 2
    b: List[Int] = List(1, 2)
    
    scala> println(a)
    List(1)
    elem

    the appended element

    returns

    a new immutable sequence consisting of all elements of this immutable sequence followed by elem.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def :+[B >: A, That](elem: B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  6. def addString(b: StringBuilder): StringBuilder

    Appends all elements of this traversable or iterator to a string builder.

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

    Example:

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = new StringBuilder()
    b: StringBuilder =
    
    scala> val h = a.addString(b)
    h: StringBuilder = 1234
    b

    the string builder to which elements are appended.

    returns

    the string builder b to which elements were appended.

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

    Appends all elements of this traversable or iterator to a string builder using a separator string.

    Appends all elements of this traversable or iterator to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method toString) of all elements of this traversable or iterator, separated by the string sep.

    Example:

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = new StringBuilder()
    b: StringBuilder =
    
    scala> a.addString(b, ", ")
    res0: StringBuilder = 1, 2, 3, 4
    b

    the string builder to which elements are appended.

    sep

    the separator string.

    returns

    the string builder b to which elements were appended.

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

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

    Appends all elements of this traversable or iterator to a string builder using start, end, and separator strings. The written text begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this traversable or iterator are separated by the string sep.

    Example:

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = new StringBuilder()
    b: StringBuilder =
    
    scala> a.addString(b , "List(" , ", " , ")")
    res5: StringBuilder = List(1, 2, 3, 4)
    b

    the string builder to which elements are appended.

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    the string builder b to which elements were appended.

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

    Aggregates the results of applying an operator to subsequent elements.

    Aggregates the results of applying an operator to subsequent elements.

    This is a more general form of fold and reduce. It is similar to foldLeft in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.

    aggregate splits the traversable or iterator into partitions and processes each partition by sequentially applying seqop, starting with z (like foldLeft). Those intermediate results are then combined by using combop (like fold). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), so combop may be invoked an arbitrary number of times (even 0).

    As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First, seqop transforms each input character to an Int and adds it to the sum (of the partition). Then, combop just needs to sum up the intermediate results of the partitions:

    List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })
    B

    the type of accumulated results

    z

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

    seqop

    an operator used to accumulate results within a partition

    combop

    an associative operator used to combine results from different partitions

    Definition Classes
    TraversableOnceGenTraversableOnce
  10. def andThen[C](k: (A) ⇒ C): PartialFunction[Int, C]

    Composes this partial function with a transformation function that gets applied to results of this partial function.

    Composes this partial function with a transformation function that gets applied to results of this partial function.

    C

    the result type of the transformation function.

    k

    the transformation function

    returns

    a partial function with the same domain as this partial function, which maps arguments x to k(this(x)).

    Definition Classes
    PartialFunctionFunction1
  11. def applyOrElse[A1 <: Int, B1 >: A](x: A1, default: (A1) ⇒ B1): B1

    Applies this partial function to the given argument when it is contained in the function domain.

    Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.

    Note that expression pf.applyOrElse(x, default) is equivalent to

    if(pf isDefinedAt x) pf(x) else default(x)

    except that applyOrElse method can be implemented more efficiently. For all partial function literals the compiler generates an applyOrElse implementation which avoids double evaluation of pattern matchers and guards. This makes applyOrElse the basis for the efficient implementation for many operations and scenarios, such as:

    • combining partial functions into orElse/andThen chains does not lead to excessive apply/isDefinedAt evaluation
    • lift and unlift do not evaluate source functions twice on each invocation
    • runWith allows efficient imperative-style combining of partial functions with conditionally applied actions

    For non-literal partial function classes with nontrivial isDefinedAt method it is recommended to override applyOrElse with custom implementation that avoids double isDefinedAt evaluation. This may result in better performance and more predictable behavior w.r.t. side effects.

    x

    the function argument

    default

    the fallback function

    returns

    the result of this function or fallback function application.

    Definition Classes
    PartialFunction
    Since

    2.10

  12. def canEqual(that: Any): Boolean

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    that

    The object with which this iterable collection should be compared

    returns

    true, if this iterable collection can possibly equal that, false otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.

    Definition Classes
    IterableLikeEquals
  13. def collect[B](pf: PartialFunction[A, B]): Seq[B]

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

    [use case]

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

    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the immutable sequence.

    returns

    a new immutable sequence 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
    TraversableLikeGenTraversableLike
    Full Signature

    def collect[B, That](pf: PartialFunction[A, B])(implicit bf: CanBuildFrom[Seq[A], B, That]): That

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

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

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

    Note: may not terminate for infinite-sized collections.

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

    pf

    the partial function

    returns

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

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

  15. def combinations(n: Int): Iterator[Seq[A]]

    Iterates over combinations.

    Iterates over combinations. A _combination_ of length n is a subsequence of the original sequence, with the elements taken in order. Thus, "xy" and "yy" are both length-2 combinations of "xyy", but "yx" is not. If there is more than one way to generate the same subsequence, only one will be returned.

    For example, "xyyy" has three different ways to generate "xy" depending on whether the first, second, or third "y" is selected. However, since all are identical, only one will be chosen. Which of the three will be taken is an implementation detail that is not defined.

    returns

    An Iterator which traverses the possible n-element combinations of this sequence.

    Definition Classes
    SeqLike
    Example:
    1. "abbbc".combinations(2) = Iterator(ab, ac, bb, bc)

  16. def companion: GenericCompanion[Seq]

    The factory companion object that builds instances of class immutable.Seq.

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

    Definition Classes
    SeqSeqGenSeqIterableIterableGenIterableTraversableTraversableGenTraversableGenericTraversableTemplate
  17. def compose[A](g: (A) ⇒ Int): (A) ⇒ A

    Composes two instances of Function1 in a new Function1, with this function applied last.

    Composes two instances of Function1 in a new Function1, with this function applied last.

    A

    the type to which function g can be applied

    g

    a function A => T1

    returns

    a new function f such that f(x) == apply(g(x))

    Definition Classes
    Function1
    Annotations
    @unspecialized()
  18. def contains[A1 >: A](elem: A1): Boolean

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

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

    Note: may not terminate for infinite-sized collections.

    elem

    the element to test.

    returns

    true if this sequence has an element that is equal (as determined by ==) to elem, false otherwise.

    Definition Classes
    SeqLike
  19. def containsSlice[B](that: GenSeq[B]): Boolean

    Tests whether this sequence contains a given sequence as a slice.

    Tests whether this sequence contains a given sequence as a slice.

    Note: may not terminate for infinite-sized collections.

    that

    the sequence to test

    returns

    true if this sequence contains a slice with the same elements as that, otherwise false.

    Definition Classes
    SeqLike
  20. def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case] Copies the elements of this immutable sequence to an array.

    [use case]

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

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    len

    the maximal number of elements to copy.

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
    Full Signature

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

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

    [use case] Copies the elements of this immutable sequence to an array.

    [use case]

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

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

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

    [use case] Copies the elements of this immutable sequence to an array.

    [use case]

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

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

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

    Copies all elements of this traversable or iterator to a buffer.

    Copies all elements of this traversable or iterator to a buffer.

    Note: will not terminate for infinite-sized collections.

    dest

    The buffer to which elements are copied.

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

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

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

    B

    the type of the elements of that

    that

    the other sequence

    p

    the test predicate, which relates elements from both sequences

    returns

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

    Definition Classes
    SeqLikeGenSeqLike
  25. def count(p: (A) ⇒ Boolean): Int

    Counts the number of elements in the traversable or iterator which satisfy a predicate.

    Counts the number of elements in the traversable or iterator which satisfy a predicate.

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    TraversableOnceGenTraversableOnce
  26. def diff(that: collection.Seq[A]): Seq[A]

    [use case] Computes the multiset difference between this immutable sequence and another sequence.

    [use case]

    Computes the multiset difference between this immutable sequence and another sequence.

    Note: will not terminate for infinite-sized collections.

    that

    the sequence of elements to remove

    returns

    a new immutable sequence which contains all elements of this immutable sequence except some of occurrences of elements that also appear in that. If an element value x appears n times in that, then the first n occurrences of x will not form part of the result, but any following occurrences will.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def diff[B >: A](that: GenSeq[B]): Seq[A]

  27. def distinct: Seq[A]

    Builds a new sequence from this sequence without any duplicate elements.

    Builds a new sequence from this sequence without any duplicate elements.

    Note: will not terminate for infinite-sized collections.

    returns

    A new sequence which contains the first occurrence of every element of this sequence.

    Definition Classes
    SeqLikeGenSeqLike
  28. def drop(n: Int): Seq[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 iterable collection.

    returns

    a iterable collection consisting of all elements of this iterable collection except the first n ones, or else the empty iterable collection, if this iterable collection has less than n elements. If n is negative, don't drop any elements.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  29. def dropRight(n: Int): Seq[A]

    Selects all elements except last n ones.

    Selects all elements except last n ones.

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

    n

    The number of elements to take

    returns

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

    Definition Classes
    IterableLike
  30. def dropWhile(p: (A) ⇒ Boolean): Seq[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.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  31. def endsWith[B](that: GenSeq[B]): Boolean

    Tests whether this sequence ends with the given sequence.

    Tests whether this sequence ends with the given sequence.

    Note: will not terminate for infinite-sized collections.

    that

    the sequence to test

    returns

    true if this sequence has that as a suffix, false otherwise.

    Definition Classes
    SeqLikeGenSeqLike
  32. def equals(that: Any): Boolean

    The equals method for arbitrary sequences.

    The equals method for arbitrary sequences. Compares this sequence to some other object.

    that

    The object to compare the sequence to

    returns

    true if that is a sequence that has the same elements as this sequence in the same order, false otherwise

    Definition Classes
    GenSeqLikeEqualsAny
  33. def exists(p: (A) ⇒ Boolean): Boolean

    Tests whether a predicate holds for at least one element of this iterable collection.

    Tests whether a predicate holds for at least one element of this iterable collection.

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

    false if this iterable collection is empty, otherwise true if the given predicate p holds for some of the elements of this iterable collection, otherwise false

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  34. def filter(p: (A) ⇒ Boolean): Seq[A]

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

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

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  35. def filterNot(p: (A) ⇒ Boolean): Seq[A]

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

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

    p

    the predicate used to test elements.

    returns

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

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

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

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

    Note: may not terminate for infinite-sized collections.

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

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  37. def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Seq[B]

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

    [use case]

    Builds a new collection by applying a function to all elements of this immutable sequence 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 immutable sequence. 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 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 immutable sequence resulting from applying the given collection-valued function f to each element of this immutable sequence and concatenating the results.

    Definition Classes
    TraversableLikeGenTraversableLikeFilterMonadic
    Full Signature

    def flatMap[B, That](f: (A) ⇒ GenTraversableOnce[B])(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  38. def flatten[B]: Seq[B]

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

    [use case]

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

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

    val xs = List(
               Set(1, 2, 3),
               Set(1, 2, 3)
             ).flatten
    // xs == List(1, 2, 3, 1, 2, 3)
    
    val ys = Set(
               List(1, 2, 3),
               List(3, 2, 1)
             ).flatten
    // ys == Set(1, 2, 3)
    B

    the type of the elements of each traversable collection.

    returns

    a new immutable sequence resulting from concatenating all element immutable sequences.

    Definition Classes
    GenericTraversableTemplate
    Full Signature

    def flatten[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): Seq[B]

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

    Folds the elements of this traversable or iterator using the specified associative binary operator.

    Folds the elements of this traversable or iterator using the specified associative binary operator.

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

    Note: will not terminate for infinite-sized collections.

    A1

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

    z

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

    op

    a binary operator that must be associative.

    returns

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

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

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

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

    Note: will not terminate for infinite-sized collections.

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

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

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

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

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

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

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

    Applies a binary operator to all elements of this iterable 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 iterable 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 iterable collection. Returns z if this iterable collection is empty.

    Definition Classes
    IterableLikeTraversableOnceGenTraversableOnce
  42. def forall(p: (A) ⇒ Boolean): Boolean

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

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

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

    true if this iterable collection is empty or the given predicate p holds for all elements of this iterable collection, otherwise false.

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  43. def foreach(f: (A) ⇒ Unit): Unit

    [use case] Applies a function f to all elements of this immutable sequence.

    [use case]

    Applies a function f to all elements of this immutable sequence.

    Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.

    f

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLikeTraversableOnceGenTraversableOnceFilterMonadic
    Full Signature

    def foreach[U](f: (A) ⇒ U): Unit

  44. def genericBuilder[B]: Builder[B, Seq[B]]

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

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

    Definition Classes
    GenericTraversableTemplate
  45. def groupBy[K](f: (A) ⇒ K): Map[K, Seq[A]]

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

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

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

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

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

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

    Definition Classes
    TraversableLikeGenTraversableLike
  46. def grouped(size: Int): Iterator[Seq[A]]

    Partitions elements in fixed size iterable collections.

    Partitions elements in fixed size iterable collections.

    size

    the number of elements per group

    returns

    An iterator producing iterable collections of size size, except the last will be less than size size if the elements don't divide evenly.

    Definition Classes
    IterableLike
    See also

    scala.collection.Iterator, method grouped

  47. def hasDefiniteSize: Boolean

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

    Tests whether this traversable collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream, the predicate returns true if all elements have been computed. It returns false if the stream is not yet evaluated to the end. Non-empty Iterators usually return false even if they were created from a collection with a known finite size.

    Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize returns true. However, checking hasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

    returns

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

    Definition Classes
    TraversableLikeTraversableOnceGenTraversableOnce
  48. def hashCode(): Int

    Hashcodes for GenSeq produce a value from the hashcodes of all the elements of the general sequence.

    Hashcodes for GenSeq produce a value from the hashcodes of all the elements of the general sequence.

    returns

    the hash code value for this object.

    Definition Classes
    GenSeqLikeAny
  49. def head: A

    Selects the first element of this iterable collection.

    Selects the first element of this iterable collection.

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

    returns

    the first element of this iterable collection.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException if the iterable collection is empty.

  50. def headOption: Option[A]

    Optionally selects the first element.

    Optionally selects the first element.

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

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  51. def indexOf(elem: A, from: Int): Int

    [use case] Finds index of first occurrence of some value in this immutable sequence after or at some start index.

    [use case]

    Finds index of first occurrence of some value in this immutable sequence after or at some start index.

    Note: may not terminate for infinite-sized collections.

    elem

    the element value to search for.

    from

    the start index

    returns

    the index >= from of the first element of this immutable sequence that is equal (as determined by ==) to elem, or -1, if none exists.

    Definition Classes
    GenSeqLike
    Full Signature

    def indexOf[B >: A](elem: B, from: Int): Int

  52. def indexOf(elem: A): Int

    [use case] Finds index of first occurrence of some value in this immutable sequence.

    [use case]

    Finds index of first occurrence of some value in this immutable sequence.

    Note: may not terminate for infinite-sized collections.

    elem

    the element value to search for.

    returns

    the index of the first element of this immutable sequence that is equal (as determined by ==) to elem, or -1, if none exists.

    Definition Classes
    GenSeqLike
    Full Signature

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

  53. def indexOfSlice[B >: A](that: GenSeq[B], from: Int): Int

    Finds first index after or at a start index where this sequence contains a given sequence as a slice.

    Finds first index after or at a start index where this sequence contains a given sequence as a slice.

    Note: may not terminate for infinite-sized collections.

    that

    the sequence to test

    from

    the start index

    returns

    the first index >= from such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

    Definition Classes
    SeqLike
  54. def indexOfSlice[B >: A](that: GenSeq[B]): Int

    Finds first index where this sequence contains a given sequence as a slice.

    Finds first index where this sequence contains a given sequence as a slice.

    Note: may not terminate for infinite-sized collections.

    that

    the sequence to test

    returns

    the first index such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

    Definition Classes
    SeqLike
  55. def indexWhere(p: (A) ⇒ Boolean, from: Int): Int

    Finds index of the first element satisfying some predicate after or at some start index.

    Finds index of the first element satisfying some predicate after or at some start index.

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    from

    the start index

    returns

    the index >= from of the first element of this sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    SeqLikeGenSeqLike
  56. def indexWhere(p: (A) ⇒ Boolean): Int

    Finds index of first element satisfying some predicate.

    Finds index of first element satisfying some predicate.

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

    the index of the first element of this general sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    GenSeqLike
  57. def indices: Range

    Produces the range of all indices of this sequence.

    Produces the range of all indices of this sequence.

    returns

    a Range value from 0 to one less than the length of this sequence.

    Definition Classes
    SeqLike
  58. def init: Seq[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 traversable collection consisting of all elements of this traversable collection except the last one.

    Definition Classes
    TraversableLikeGenTraversableLike
    Exceptions thrown

    UnsupportedOperationException if the traversable collection is empty.

  59. def inits: Iterator[Seq[A]]

    Iterates over the inits of this traversable collection.

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

    returns

    an iterator over all the inits of this traversable collection

    Definition Classes
    TraversableLike
    Example:
    1. List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)

  60. def intersect(that: collection.Seq[A]): Seq[A]

    [use case] Computes the multiset intersection between this immutable sequence and another sequence.

    [use case]

    Computes the multiset intersection between this immutable sequence and another sequence.

    Note: may not terminate for infinite-sized collections.

    that

    the sequence of elements to intersect with.

    returns

    a new immutable sequence which contains all elements of this immutable sequence which also appear in that. If an element value x appears n times in that, then the first n occurrences of x will be retained in the result, but any following occurrences will be omitted.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def intersect[B >: A](that: GenSeq[B]): Seq[A]

  61. def isDefinedAt(idx: Int): Boolean

    Tests whether this general sequence contains given index.

    Tests whether this general sequence contains given index.

    The implementations of methods apply and isDefinedAt turn a Seq[A] into a PartialFunction[Int, A].

    idx

    the index to test

    returns

    true if this general sequence contains an element at position idx, false otherwise.

    Definition Classes
    GenSeqLike
  62. def isEmpty: Boolean

    Tests whether this sequence is empty.

    Tests whether this sequence is empty.

    returns

    true if the sequence contain no elements, false otherwise.

    Definition Classes
    SeqLikeIterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  63. final def isTraversableAgain: Boolean

    Tests whether this traversable collection can be repeatedly traversed.

    Tests whether this traversable collection can be repeatedly traversed.

    returns

    true

    Definition Classes
    TraversableLikeGenTraversableLikeGenTraversableOnce
  64. 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 traversable collection.

    Definition Classes
    TraversableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException If the traversable collection is empty.

  65. def lastIndexOf(elem: A, end: Int): Int

    [use case] Finds index of last occurrence of some value in this immutable sequence before or at a given end index.

    [use case]

    Finds index of last occurrence of some value in this immutable sequence before or at a given end index.

    elem

    the element value to search for.

    end

    the end index.

    returns

    the index <= end of the last element of this immutable sequence that is equal (as determined by ==) to elem, or -1, if none exists.

    Definition Classes
    GenSeqLike
    Full Signature

    def lastIndexOf[B >: A](elem: B, end: Int): Int

  66. def lastIndexOf(elem: A): Int

    [use case] Finds index of last occurrence of some value in this immutable sequence.

    [use case]

    Finds index of last occurrence of some value in this immutable sequence.

    Note: will not terminate for infinite-sized collections.

    elem

    the element value to search for.

    returns

    the index of the last element of this immutable sequence that is equal (as determined by ==) to elem, or -1, if none exists.

    Definition Classes
    GenSeqLike
    Full Signature

    def lastIndexOf[B >: A](elem: B): Int

  67. def lastIndexOfSlice[B >: A](that: GenSeq[B], end: Int): Int

    Finds last index before or at a given end index where this sequence contains a given sequence as a slice.

    Finds last index before or at a given end index where this sequence contains a given sequence as a slice.

    that

    the sequence to test

    end

    the end index

    returns

    the last index <= end such that the elements of this sequence starting at this index match the elements of sequence that, or -1 of no such subsequence exists.

    Definition Classes
    SeqLike
  68. def lastIndexOfSlice[B >: A](that: GenSeq[B]): Int

    Finds last index where this sequence contains a given sequence as a slice.

    Finds last index where this sequence contains a given sequence as a slice.

    Note: will not terminate for infinite-sized collections.

    that

    the sequence to test

    returns

    the last index such that the elements of this sequence starting a this index match the elements of sequence that, or -1 of no such subsequence exists.

    Definition Classes
    SeqLike
  69. def lastIndexWhere(p: (A) ⇒ Boolean, end: Int): Int

    Finds index of last element satisfying some predicate before or at given end index.

    Finds index of last element satisfying some predicate before or at given end index.

    p

    the predicate used to test elements.

    returns

    the index <= end of the last element of this sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    SeqLikeGenSeqLike
  70. def lastIndexWhere(p: (A) ⇒ Boolean): Int

    Finds index of last element satisfying some predicate.

    Finds index of last element satisfying some predicate.

    Note: will not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

    the index of the last element of this general sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    GenSeqLike
  71. 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 traversable collection$ if it is nonempty, None if it is empty.

    Definition Classes
    TraversableLikeGenTraversableLike
  72. def lengthCompare(len: Int): Int

    Compares the length of this sequence to a test value.

    Compares the length of this sequence to a test value.

    len

    the test value that gets compared with the length.

    returns

    A value x where

    x <  0       if this.length <  len
    x == 0       if this.length == len
    x >  0       if this.length >  len

    The method as implemented here does not call length directly; its running time is O(length min len) instead of O(length). The method should be overwritten if computing length is cheap.

    Definition Classes
    SeqLike
  73. def lift: (Int) ⇒ Option[A]

    Turns this partial function into a plain function returning an Option result.

    Turns this partial function into a plain function returning an Option result.

    returns

    a function that takes an argument x to Some(this(x)) if this is defined for x, and to None otherwise.

    Definition Classes
    PartialFunction
    See also

    Function.unlift

  74. def map[B](f: (A) ⇒ B): Seq[B]

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

    [use case]

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

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new immutable sequence resulting from applying the given function f to each element of this immutable sequence and collecting the results.

    Definition Classes
    TraversableLikeGenTraversableLikeFilterMonadic
    Full Signature

    def map[B, That](f: (A) ⇒ B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  75. def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

    the largest element of this immutable sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

    Exceptions thrown

    UnsupportedOperationException if this immutable sequence is empty.

  76. def maxBy[B](f: (A) ⇒ B): A

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

    [use case]

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

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this immutable sequence with the largest value measured by function f.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

    Exceptions thrown

    UnsupportedOperationException if this immutable sequence is empty.

  77. def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

    the smallest element of this immutable sequence

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

    Exceptions thrown

    UnsupportedOperationException if this immutable sequence is empty.

  78. def minBy[B](f: (A) ⇒ B): A

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

    [use case]

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

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this immutable sequence with the smallest value measured by function f.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

    Exceptions thrown

    UnsupportedOperationException if this immutable sequence is empty.

  79. def mkString: String

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

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

    returns

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

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

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

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

    sep

    the separator string.

    returns

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

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

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

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

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

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    a string representation of this traversable or iterator. The resulting string begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this traversable or iterator are separated by the string sep.

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

  82. def nonEmpty: Boolean

    Tests whether the traversable or iterator is not empty.

    Tests whether the traversable or iterator is not empty.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  83. def orElse[A1 <: Int, B1 >: A](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]

    Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

    Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

    A1

    the argument type of the fallback function

    B1

    the result type of the fallback function

    that

    the fallback function

    returns

    a partial function which has as domain the union of the domains of this partial function and that. The resulting partial function takes x to this(x) where this is defined, and to that(x) where it is not.

    Definition Classes
    PartialFunction
  84. def padTo(len: Int, elem: A): Seq[A]

    [use case] A copy of this immutable sequence with an element value appended until a given target length is reached.

    [use case]

    A copy of this immutable sequence with an element value appended until a given target length is reached.

    len

    the target length

    elem

    the padding value

    returns

    a new immutable sequence consisting of all elements of this immutable sequence followed by the minimal number of occurrences of elem so that the resulting immutable sequence has a length of at least len.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def padTo[B >: A, That](len: Int, elem: B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  85. def par: ParSeq[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
  86. def partition(p: (A) ⇒ Boolean): (Seq[A], Seq[A])

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

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

    p

    the predicate on which to partition.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  87. def patch(from: Int, that: GenSeq[A], replaced: Int): Seq[A]

    [use case] Produces a new immutable sequence where a slice of elements in this immutable sequence is replaced by another sequence.

    [use case]

    Produces a new immutable sequence where a slice of elements in this immutable sequence is replaced by another sequence.

    from

    the index of the first replaced element

    replaced

    the number of elements to drop in the original immutable sequence

    returns

    a new immutable sequence consisting of all elements of this immutable sequence except that replaced elements starting from from are replaced by patch.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def patch[B >: A, That](from: Int, patch: GenSeq[B], replaced: Int)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  88. def permutations: Iterator[Seq[A]]

    Iterates over distinct permutations.

    Iterates over distinct permutations.

    returns

    An Iterator which traverses the distinct permutations of this sequence.

    Definition Classes
    SeqLike
    Example:
    1. "abb".permutations = Iterator(abb, bab, bba)

  89. def prefixLength(p: (A) ⇒ Boolean): Int

    Returns the length of the longest prefix whose elements all satisfy some predicate.

    Returns the length of the longest prefix whose elements all satisfy some predicate.

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

    the length of the longest prefix of this general sequence such that every element of the segment satisfies the predicate p.

    Definition Classes
    GenSeqLike
  90. 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 immutable sequence 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 immutable sequence and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

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

    Reduces the elements of this traversable or iterator using the specified associative binary operator.

    Reduces the elements of this traversable or iterator using the specified associative binary operator.

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

    A1

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

    op

    A binary operator that must be associative.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

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

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

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

    Note: will not terminate for infinite-sized collections.

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

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

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

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

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

    Definition Classes
    TraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this traversable or iterator is empty.

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

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

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

    Note: will not terminate for infinite-sized collections.

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

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

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

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

    Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.

    Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.

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

    A1

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

    op

    A binary operator that must be associative.

    returns

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

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

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

    Applies a binary operator to all elements of this iterable 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 iterable 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 iterable collection.

    Definition Classes
    IterableLikeTraversableOnceGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this iterable collection is empty.

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

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

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

    Note: will not terminate for infinite-sized collections.

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

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  97. def repr: Seq[A]

    The collection of type traversable collection underlying this TraversableLike object.

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

    Definition Classes
    TraversableLikeGenTraversableLike
  98. def reverse: Seq[A]

    Returns new sequence with elements in reversed order.

    Returns new sequence with elements in reversed order.

    Note: will not terminate for infinite-sized collections.

    returns

    A new sequence with all elements of this sequence in reversed order.

    Definition Classes
    SeqLikeGenSeqLike
  99. def reverseIterator: Iterator[A]

    An iterator yielding elements in reversed order.

    An iterator yielding elements in reversed order.

    Note: will not terminate for infinite-sized collections.

    Note: xs.reverseIterator is the same as xs.reverse.iterator but might be more efficient.

    returns

    an iterator yielding the elements of this sequence in reversed order

    Definition Classes
    SeqLike
  100. def reverseMap[B](f: (A) ⇒ B): Seq[B]

    [use case] Builds a new collection by applying a function to all elements of this immutable sequence and collecting the results in reversed order.

    [use case]

    Builds a new collection by applying a function to all elements of this immutable sequence and collecting the results in reversed order.

    Note: will not terminate for infinite-sized collections.

    Note: xs.reverseMap(f) is the same as xs.reverse.map(f) but might be more efficient.

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new immutable sequence resulting from applying the given function f to each element of this immutable sequence and collecting the results in reversed order.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def reverseMap[B, That](f: (A) ⇒ B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  101. def runWith[U](action: (A) ⇒ U): (Int) ⇒ Boolean

    Composes this partial function with an action function which gets applied to results of this partial function.

    Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.

    Note that expression pf.runWith(action)(x) is equivalent to

    if(pf isDefinedAt x) { action(pf(x)); true } else false

    except that runWith is implemented via applyOrElse and thus potentially more efficient. Using runWith avoids double evaluation of pattern matchers and guards for partial function literals.

    action

    the action function

    returns

    a function which maps arguments x to isDefinedAt(x). The resulting function runs action(this(x)) where this is defined.

    Definition Classes
    PartialFunction
    Since

    2.10

    See also

    applyOrElse.

  102. def sameElements(that: GenIterable[A]): Boolean

    [use case] Checks if the other iterable collection contains the same elements in the same order as this immutable sequence.

    [use case]

    Checks if the other iterable collection contains the same elements in the same order as this immutable sequence.

    Note: will not terminate for infinite-sized collections.

    that

    the collection to compare with.

    returns

    true, if both collections contain the same elements in the same order, false otherwise.

    Definition Classes
    IterableLikeGenIterableLike
    Full Signature

    def sameElements[B >: A](that: GenIterable[B]): Boolean

  103. def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Seq[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 traversable collection containing the prefix scan of the elements in this traversable collection

    Definition Classes
    TraversableLikeGenTraversableLike
  104. def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[Seq[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 the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    TraversableLikeGenTraversableLike
  105. def scanRight[B, That](z: B)(op: (A, B) ⇒ B)(implicit bf: CanBuildFrom[Seq[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 the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    TraversableLikeGenTraversableLike
    Annotations
    @migration
    Migration

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

  106. def segmentLength(p: (A) ⇒ Boolean, from: Int): Int

    Computes length of longest segment whose elements all satisfy some predicate.

    Computes length of longest segment whose elements all satisfy some predicate.

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    from

    the index where the search starts.

    returns

    the length of the longest segment of this sequence starting from index from such that every element of the segment satisfies the predicate p.

    Definition Classes
    SeqLikeGenSeqLike
  107. def seq: Seq[A]

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

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

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

    returns

    a sequential view of the collection.

    Definition Classes
    SeqSeqGenSeqGenSeqLikeIterableIterableGenIterableTraversableTraversableGenTraversableParallelizableTraversableOnceGenTraversableOnce
  108. def size: Int

    The size of this sequence, equivalent to length.

    The size of this sequence, equivalent to length.

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this sequence.

    Definition Classes
    SeqLikeGenTraversableLikeTraversableOnceGenTraversableOnce
  109. def slice(from: Int, until: Int): Seq[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.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  110. def sliding(size: Int, step: Int): Iterator[Seq[A]]

    Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

    Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

    size

    the number of elements per group

    step

    the distance between the first elements of successive groups

    returns

    An iterator producing iterable collections of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

    Definition Classes
    IterableLike
    See also

    scala.collection.Iterator, method sliding

  111. def sliding(size: Int): Iterator[Seq[A]]

    Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) The "sliding window" step is set to one.

    Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.) The "sliding window" step is set to one.

    size

    the number of elements per group

    returns

    An iterator producing iterable collections of size size, except the last element (which may be the only element) will be truncated if there are fewer than size elements remaining to be grouped.

    Definition Classes
    IterableLike
    See also

    scala.collection.Iterator, method sliding

  112. def sortBy[B](f: (A) ⇒ B)(implicit ord: math.Ordering[B]): Seq[A]

    Sorts this Seq according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.

    Sorts this Seq according to the Ordering which results from transforming an implicitly given Ordering with a transformation function.

    B

    the target type of the transformation f, and the type where the ordering ord is defined.

    f

    the transformation function mapping elements to some other domain B.

    ord

    the ordering assumed on domain B.

    returns

    a sequence consisting of the elements of this sequence sorted according to the ordering where x < y if ord.lt(f(x), f(y)).

    Definition Classes
    SeqLike
    Example:
    1. val words = "The quick brown fox jumped over the lazy dog".split(' ')
      // this works because scala.Ordering will implicitly provide an Ordering[Tuple2[Int, Char]]
      words.sortBy(x => (x.length, x.head))
      res0: Array[String] = Array(The, dog, fox, the, lazy, over, brown, quick, jumped)
    See also

    scala.math.Ordering Note: will not terminate for infinite-sized collections.

  113. def sortWith(lt: (A, A) ⇒ Boolean): Seq[A]

    Sorts this sequence according to a comparison function.

    Sorts this sequence according to a comparison function.

    Note: will not terminate for infinite-sized collections.

    The sort is stable. That is, elements that are equal (as determined by lt) appear in the same order in the sorted sequence as in the original.

    lt

    the comparison function which tests whether its first argument precedes its second argument in the desired ordering.

    returns

    a sequence consisting of the elements of this sequence sorted according to the comparison function lt.

    Definition Classes
    SeqLike
    Example:
    1. List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) =
      List("Bob", "John", "Steve", "Tom")
  114. def sorted[B >: A](implicit ord: math.Ordering[B]): Seq[A]

    Sorts this sequence according to an Ordering.

    Sorts this sequence according to an Ordering.

    The sort is stable. That is, elements that are equal (as determined by lt) appear in the same order in the sorted sequence as in the original.

    ord

    the ordering to be used to compare elements.

    returns

    a sequence consisting of the elements of this sequence sorted according to the ordering ord.

    Definition Classes
    SeqLike
    See also

    scala.math.Ordering

  115. def span(p: (A) ⇒ Boolean): (Seq[A], Seq[A])

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

    Splits this traversable 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 traversable collection whose elements all satisfy p, and the rest of this traversable collection.

    Definition Classes
    TraversableLikeGenTraversableLike
  116. def splitAt(n: Int): (Seq[A], Seq[A])

    Splits this traversable collection into two at a given position.

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

    Definition Classes
    TraversableLikeGenTraversableLike
  117. def startsWith[B](that: GenSeq[B], offset: Int): Boolean

    Tests whether this sequence contains the given sequence at a given index.

    Tests whether this sequence contains the given sequence at a given index.

    Note: If the both the receiver object this and the argument that are infinite sequences this method may not terminate.

    that

    the sequence to test

    offset

    the index where the sequence is searched.

    returns

    true if the sequence that is contained in this sequence at index offset, otherwise false.

    Definition Classes
    SeqLikeGenSeqLike
  118. def startsWith[B](that: GenSeq[B]): Boolean

    Tests whether this general sequence starts with the given sequence.

    Tests whether this general sequence starts with the given sequence.

    that

    the sequence to test

    returns

    true if this collection has that as a prefix, false otherwise.

    Definition Classes
    GenSeqLike
  119. 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 traversable collection. By default the string prefix is the simple name of the collection class traversable collection.

    Definition Classes
    TraversableLikeGenTraversableLike
  120. 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 immutable sequence 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 immutable sequence and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

  121. def tail: Seq[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 traversable collection consisting of all elements of this traversable collection except the first one.

    Definition Classes
    TraversableLikeGenTraversableLike
    Exceptions thrown

    java.lang.UnsupportedOperationException if the traversable collection is empty.

  122. def tails: Iterator[Seq[A]]

    Iterates over the tails of this traversable collection.

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

    returns

    an iterator over all the tails of this traversable collection

    Definition Classes
    TraversableLike
    Example:
    1. List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)

  123. def take(n: Int): Seq[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 iterable collection.

    returns

    a iterable collection consisting only of the first n elements of this iterable collection, or else the whole iterable collection, if it has less than n elements. If n is negative, returns an empty iterable collection.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  124. def takeRight(n: Int): Seq[A]

    Selects last n elements.

    Selects last n elements.

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

    n

    the number of elements to take

    returns

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

    Definition Classes
    IterableLike
  125. def takeWhile(p: (A) ⇒ Boolean): Seq[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.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  126. def to[Col[_]]: Col[A]

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

    [use case]

    Converts this immutable sequence 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 immutable sequence.

    Definition Classes
    TraversableLikeTraversableOnceGenTraversableOnce
    Full Signature

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

  127. def toArray: Array[A]

    [use case] Converts this immutable sequence to an array.

    [use case]

    Converts this immutable sequence to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this immutable sequence. An ClassTag must be available for the element type of this immutable sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

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

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

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

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  129. def toIndexedSeq: IndexedSeq[A]

    Converts this traversable or iterator to an indexed sequence.

    Converts this traversable or iterator to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  130. def toIterable: collection.Iterable[A]

    Returns this iterable collection as an iterable collection.

    Returns this iterable collection as an iterable collection.

    A new collection will not be built; lazy collections will stay lazy.

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterable containing all elements of this iterable collection.

    Definition Classes
    IterableLikeTraversableOnceGenTraversableOnce
  131. def toIterator: Iterator[A]

    Returns an Iterator over the elements in this iterable collection.

    Returns an Iterator over the elements in this iterable collection. Produces the same result as iterator.

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterator containing all elements of this iterable collection.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableOnce
    Annotations
    @deprecatedOverriding( message = ... , since = "2.11.0" )
  132. def toList: scala.List[A]

    Converts this traversable or iterator to a list.

    Converts this traversable or iterator to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this traversable or iterator.

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

    [use case] Converts this immutable sequence to a map.

    [use case]

    Converts this immutable sequence 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 immutable sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Full Signature

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

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

    Converts this immutable sequence to a sequence.

    Converts this immutable sequence to a sequence.

    Note: will not terminate for infinite-sized collections.

    A new collection will not be built; in particular, lazy sequences will stay lazy.

    returns

    a sequence containing all elements of this immutable sequence.

    Definition Classes
    SeqSeqLikeGenSeqLikeTraversableOnceGenTraversableOnce
  136. def toSet[B >: A]: Set[B]

    Converts this traversable or iterator to a set.

    Converts this traversable or iterator to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  137. def toStream: Stream[A]

    Converts this iterable collection to a stream.

    Converts this iterable collection to a stream.

    returns

    a stream containing all elements of this iterable collection.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableOnce
  138. def toString(): String

    Converts this sequence to a string.

    Converts this sequence to a string.

    returns

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

    Definition Classes
    SeqLikeTraversableLikeAny
  139. def toTraversable: collection.Traversable[A]

    Converts this traversable collection to an unspecified Traversable.

    Converts this traversable 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 traversable collection.

    Definition Classes
    TraversableLikeTraversableOnceGenTraversableOnce
    Annotations
    @deprecatedOverriding( message = ... , since = "2.11.0" )
  140. def toVector: scala.Vector[A]

    Converts this traversable or iterator to a Vector.

    Converts this traversable or iterator to a Vector.

    Note: will not terminate for infinite-sized collections.

    returns

    a vector containing all elements of this traversable or iterator.

    Definition Classes
    TraversableOnceGenTraversableOnce
  141. def transpose[B](implicit asTraversable: (A) ⇒ GenTraversableOnce[B]): Seq[Seq[B]]

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

    Transposes this collection of traversable collections into a collection of 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(4, 5, 6)).transpose
    // xs == List(
    //         List(1, 4),
    //         List(2, 5),
    //         List(3, 6))
    
    val ys = Vector(
               List(1, 2, 3),
               List(4, 5, 6)).transpose
    // ys == Vector(
    //         Vector(1, 4),
    //         Vector(2, 5),
    //         Vector(3, 6))
    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.

  142. def union(that: collection.Seq[A]): Seq[A]

    [use case] Produces a new sequence which contains all elements of this immutable sequence and also all elements of a given sequence.

    [use case]

    Produces a new sequence which contains all elements of this immutable sequence and also all elements of a given sequence. xs union ys is equivalent to xs ++ ys.

    Another way to express this is that xs union ys computes the order-preserving multi-set union of xs and ys. union is hence a counter-part of diff and intersect which also work on multi-sets.

    Note: will not terminate for infinite-sized collections.

    that

    the sequence to add.

    returns

    a new immutable sequence which contains all elements of this immutable sequence followed by all elements of that.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def union[B >: A, That](that: GenSeq[B])(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  143. def unzip[A1, A2](implicit asPair: (A) ⇒ (A1, A2)): (Seq[A1], Seq[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.

    val xs = Traversable(
               (1, "one"),
               (2, "two"),
               (3, "three")).unzip
    // xs == (Traversable(1, 2, 3),
    //        Traversable(one, two, three))
    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 of collections, containing the first, respectively second half of each element pair of this collection.

    Definition Classes
    GenericTraversableTemplate
  144. def unzip3[A1, A2, A3](implicit asTriple: (A) ⇒ (A1, A2, A3)): (Seq[A1], Seq[A2], Seq[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.

    val xs = Traversable(
               (1, "one", '1'),
               (2, "two", '2'),
               (3, "three", '3')).unzip3
    // xs == (Traversable(1, 2, 3),
    //        Traversable(one, two, three),
    //        Traversable(1, 2, 3))
    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 of collections, containing the first, second, respectively third member of each element triple of this collection.

    Definition Classes
    GenericTraversableTemplate
  145. def updated(index: Int, elem: A): Seq[A]

    [use case] A copy of this immutable sequence with one single replaced element.

    [use case]

    A copy of this immutable sequence with one single replaced element.

    index

    the position of the replacement

    elem

    the replacing element

    returns

    a copy of this immutable sequence with the element at position index replaced by elem.

    Definition Classes
    SeqLikeGenSeqLike
    Full Signature

    def updated[B >: A, That](index: Int, elem: B)(implicit bf: CanBuildFrom[Seq[A], B, That]): That

  146. def view(from: Int, until: Int): SeqView[A, Seq[A]]

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

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

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

    Note: view(from, to) is equivalent to view.slice(from, to)

    from

    the index of the first element of the view

    until

    the index of the element following the view

    returns

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

    Definition Classes
    SeqLikeIterableLikeTraversableLike
  147. def view: SeqView[A, Seq[A]]

    Creates a non-strict view of this sequence.

    Creates a non-strict view of this sequence.

    returns

    a non-strict view of this sequence.

    Definition Classes
    SeqLikeIterableLikeTraversableLike
  148. def withFilter(p: (A) ⇒ Boolean): FilterMonadic[A, Seq[A]]

    Creates a non-strict filter of this traversable collection.

    Creates a non-strict filter of this traversable collection.

    Note: the difference between c filter p and c withFilter p is that the former creates a new collection, whereas the latter only restricts the domain of subsequent map, flatMap, foreach, and withFilter operations.

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

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    TraversableLikeFilterMonadic
  149. def zip[B](that: GenIterable[B]): Seq[(A, B)]

    [use case] Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    returns

    a new immutable sequence containing pairs consisting of corresponding elements of this immutable sequence and that. The length of the returned collection is the minimum of the lengths of this immutable sequence and that.

    Definition Classes
    IterableLikeGenIterableLike
    Full Signature

    def zip[A1 >: A, B, That](that: GenIterable[B])(implicit bf: CanBuildFrom[Seq[A], (A1, B), That]): That

  150. def zipAll[B](that: collection.Iterable[B], thisElem: A, thatElem: B): Seq[(A, B)]

    [use case] Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a immutable sequence formed from this immutable sequence and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    thisElem

    the element to be used to fill up the result if this immutable sequence is shorter than that.

    thatElem

    the element to be used to fill up the result if that is shorter than this immutable sequence.

    returns

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

    Definition Classes
    IterableLikeGenIterableLike
    Full Signature

    def zipAll[B, A1 >: A, That](that: GenIterable[B], thisElem: A1, thatElem: B)(implicit bf: CanBuildFrom[Seq[A], (A1, B), That]): That

  151. def zipWithIndex: Seq[(A, Int)]

    [use case] Zips this immutable sequence with its indices.

    [use case]

    Zips this immutable sequence with its indices.

    returns

    A new immutable sequence containing pairs consisting of all elements of this immutable sequence paired with their index. Indices start at 0.

    Definition Classes
    IterableLikeGenIterableLike
    Full Signature

    def zipWithIndex[A1 >: A, That](implicit bf: CanBuildFrom[Seq[A], (A1, Int), That]): That

    Example:
    1. List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))

Shadowed Implicit Value Members

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

Deprecated Value Members

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

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

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

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

    Examples:

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

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

    Note: will not terminate for infinite-sized collections.

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

    B

    the result type of the binary operator.

    z

    the start value.

    op

    the binary operator.

    returns

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

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

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

    Definition Classes
    TraversableOnceGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldLeft instead of /:

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

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

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

    Note: :\ is alternate syntax for foldRight; xs :\ z is the same as xs foldRight z.

    Note: will not terminate for infinite-sized collections.

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

    Examples:

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

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

    the result type of the binary operator.

    z

    the start value

    op

    the binary operator

    returns

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

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

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

    Definition Classes
    TraversableOnceGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldRight instead of :\