scala.collection

SeqLike

trait SeqLike[+A, +Repr] extends IterableLike[A, Repr] with GenSeqLike[A, Repr] with Parallelizable[A, ParSeq[A]]

A template trait for sequences of type Seq[A]

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 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.

Self Type
SeqLike[A, Repr]
Source
SeqLike.scala
Linear Supertypes
GenSeqLike[A, Repr], IterableLike[A, Repr], GenIterableLike[A, Repr], TraversableLike[A, Repr], GenTraversableLike[A, Repr], Parallelizable[A, ParSeq[A]], TraversableOnce[A], GenTraversableOnce[A], FilterMonadic[A, Repr], HasNewBuilder[A, Repr], Equals, AnyRef, Any
Known Subclasses
::, Appended, Appended, ArrayBuffer, ArrayLike, ArrayOps, ArraySeq, ArrayStack, Atom, Buffer, BufferLike, BufferProxy, BufferWrapper, ByOne, Comment, Cons, Content, Document, DoubleLinkedList, DoubleLinkedListLike, DroppedWhile, DroppedWhile, DroppedWhile, Elem, Empty, EmptyView, EmptyView, EntityRef, Exclusive, Filtered, Filtered, Filtered, FlatMapped, FlatMapped, Forced, Forced, Group, Impl, Inclusive, Inclusive, IndexedSeq, IndexedSeq, IndexedSeq, IndexedSeqLike, IndexedSeqLike, IndexedSeqOptimized, IndexedSeqOptimized, IndexedSeqView, JListWrapper, LinearSeq, LinearSeq, LinearSeq, LinearSeqLike, LinearSeqOptimized, LinkedList, LinkedListLike, List, ListBuffer, Mapped, Mapped, MutableList, Nil, Node, NodeBuffer, NodeSeq, NumericRange, ObservableBuffer, PCData, PagedSeq, Patched, Patched, Prepended, Prepended, ProcInstr, Queue, Queue, QueueProxy, Range, RefBuffer, ResizableArray, Reversed, Reversed, Reversed, Script, Seq, Seq, Seq, SeqForwarder, SeqLike, SeqProxy, SeqProxyLike, SeqView, SeqViewLike, Sliced, Sliced, Sliced, SpecialNode, Stack, Stack, StackProxy, Stream, StreamView, StreamViewLike, StringBuilder, StringLike, StringOps, SynchronizedBuffer, SynchronizedQueue, SynchronizedStack, TakenWhile, TakenWhile, TakenWhile, Text, Transformed, Transformed, Transformed, Unparsed, UnrolledBuffer, Vector, WrappedArray, WrappedString, Zipped, Zipped, ZippedAll, ZippedAll, items, ofBoolean, ofBoolean, ofByte, ofByte, ofChar, ofChar, ofDouble, ofDouble, ofFloat, ofFloat, ofInt, ofInt, ofLong, ofLong, ofRef, ofRef, ofShort, ofShort, ofUnit, ofUnit, pages
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Inherited
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  1. SeqLike
  2. GenSeqLike
  3. IterableLike
  4. GenIterableLike
  5. TraversableLike
  6. GenTraversableLike
  7. Parallelizable
  8. TraversableOnce
  9. GenTraversableOnce
  10. FilterMonadic
  11. HasNewBuilder
  12. Equals
  13. AnyRef
  14. Any
Visibility
  1. Public
  2. All

Type Members

  1. type Self = Repr

    The type implementing this traversable

    The type implementing this traversable

    Attributes
    protected
    Definition Classes
    TraversableLike
  2. class WithFilter extends FilterMonadic[A, Repr]

    A class supporting filtered operations.

Abstract Value Members

  1. 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 = LinkedList(1, 2, 3, 4, 5)
       x: scala.collection.mutable.LinkedList[Int] = LinkedList(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
  4. abstract def newBuilder: Builder[A, Repr]

    Creates a new builder for this collection type.

    Creates a new builder for this collection type.

    Attributes
    protected[this]
    Definition Classes
    TraversableLikeHasNewBuilder
  5. abstract def seq: Seq[A]

    Definition Classes
    GenSeqLikeParallelizableGenTraversableOnce

Concrete Value Members

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

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

    Test two objects for inequality.

    Test two objects for inequality.

    returns

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

    Definition Classes
    Any
  3. final def ##(): Int

    Equivalent to x.hashCode except for boxed numeric types and null.

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

    returns

    a hash value consistent with ==

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

    [use case]

    [use case]
    B

    the element type of the returned collection.

    that

    the traversable to append.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  5. def ++:[B >: A, That](that: Traversable[B])(implicit bf: CanBuildFrom[Repr, 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 sequence followed by all elements of that.

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

    [use case]

    [use case]
    B

    the element type of the returned collection.

    that

    the traversable to append.

    returns

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

    Definition Classes
    TraversableLike
  7. def +:(elem: A): Seq[A]

    [use case]

    [use case]
    elem

    the prepended element

    returns

    a new collection of type That consisting of elem followed by all elements of this sequence.

    Definition Classes
    SeqLikeGenSeqLike
  8. def /:[B](z: B)(op: (B, A) ⇒ B): B

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

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

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

    Examples:

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

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

    Note: will not terminate for infinite-sized collections.

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

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

    where x1, ..., xn are the elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  9. def /:\[A1 >: A](z: A1)(op: (A1, A1) ⇒ A1): A1

    A syntactic sugar for out of order folding.

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

    Example:

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
    
         scala> val b = (a /:\ 5)(_+_)
         b: Int = 15
    
    Definition Classes
    GenTraversableOnce
  10. def :+(elem: A): Seq[A]

    [use case]

    [use case]
    elem

    the appended element

    returns

    a new collection of type That consisting of all elements of this sequence followed by elem.

    Definition Classes
    SeqLikeGenSeqLike
  11. def :\[B](z: B)(op: (A, B) ⇒ B): B

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

    Applies a binary operator to all elements of this sequence 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.

    Examples:

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

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

    the result type of the binary operator.

    z

    the start value

    op

    the binary operator

    returns

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

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

    where x1, ..., xn are the elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  12. final def ==(arg0: AnyRef): Boolean

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

    Test two objects for equality.

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

    returns

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

    Definition Classes
    Any
  14. def addString(b: StringBuilder): StringBuilder

    Appends all elements of this sequence to a string builder.

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

    Example:

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

    the string builder to which elements are appended.

    returns

    the string builder b to which elements were appended.

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

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

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

    Example:

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(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
  16. def addString(b: StringBuilder, start: String, sep: String, end: String): StringBuilder

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

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

    Example:

         scala> val a = LinkedList(1,2,3,4)
         a: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2, 3, 4)
    
         scala> val b = new StringBuilder()
         b: StringBuilder =
    
         scala> a.addString(b, "LinkedList(", ", ", ")")
         res1: StringBuilder = LinkedList(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
  17. def aggregate[B](z: B)(seqop: (B, A) ⇒ B, combop: (B, B) ⇒ B): B

    Aggregates the results of applying an operator to subsequent elements.

    Aggregates the results of applying an operator to subsequent elements.

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

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

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

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

    B

    the type of accumulated results

    z

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

    seqop

    an operator used to accumulate results within a partition

    combop

    an associative operator used to combine results from different partitions

    Definition Classes
    TraversableOnceGenTraversableOnce
  18. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

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

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown
    ClassCastException

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

  19. 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 sequence should be compared

    returns

    true, if this sequence 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
  20. def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

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

    [use case]

    [use case]
    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the sequence.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  22. def collectFirst[B](pf: PartialFunction[A, B]): Option[B]

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

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

    Note: may not terminate for infinite-sized collections.

    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)

  23. def combinations(n: Int): Iterator[Repr]

    Iterates over combinations.

    Iterates over combinations.

    returns

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

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

  24. def contains(elem: Any): 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 is equal (wrt ==) to elem, false otherwise.

  25. 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.

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

    [use case]

    [use case]
    xs

    the array to fill.

    start

    the starting index.

    len

    the maximal number of elements to copy.

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  27. def copyToArray(xs: Array[A]): Unit

    [use case]

    [use case]
    xs

    the array to fill.

    Definition Classes
    TraversableOnceGenTraversableOnce
  28. def copyToArray(xs: Array[A], start: Int): Unit

    [use case]

    [use case]
    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    TraversableOnceGenTraversableOnce
  29. def copyToBuffer[B >: A](dest: Buffer[B]): Unit

    Copies all elements of this sequence to a buffer.

    Copies all elements of this sequence to a buffer.

    Note: will not terminate for infinite-sized collections.

    dest

    The buffer to which elements are copied.

    Definition Classes
    TraversableOnce
  30. 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
  31. def count(p: (A) ⇒ Boolean): Int

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

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

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

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

    [use case]

    [use case]
    that

    the sequence of elements to remove

    returns

    a new collection of type That which contains all elements of this 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
  33. def distinct: Repr

    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
  34. def drop(n: Int): Repr

    Selects all elements except first n ones.

    Selects all elements except first n ones.

    n

    the number of elements to drop from this sequence.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  35. def dropRight(n: Int): Repr

    Selects all elements except last n ones.

    Selects all elements except last n ones.

    n

    The number of elements to take

    returns

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

    Definition Classes
    IterableLike
  36. def dropWhile(p: (A) ⇒ Boolean): Repr

    Drops longest prefix of elements that satisfy a predicate.

    Drops longest prefix of elements that satisfy a predicate.

    p

    The predicate used to test elements.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  37. 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
  38. final def eq(arg0: AnyRef): Boolean

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

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

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

    • It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.
    • For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false.
    • null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    returns

    true if the argument is a reference to the receiver object; false otherwise.

    Definition Classes
    AnyRef
  39. 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
    GenSeqLikeEquals → AnyRef → Any
  40. def exists(p: (A) ⇒ Boolean): Boolean

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

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

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  41. def filter(p: (A) ⇒ Boolean): Repr

    Selects all elements of this sequence which satisfy a predicate.

    Selects all elements of this sequence which satisfy a predicate.

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  42. def filterNot(p: (A) ⇒ Boolean): Repr

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

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

    p

    the predicate used to test elements.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  43. def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
    Note

    not specified by SLS as a member of AnyRef

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

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

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

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

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

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

    [use case]

    [use case]
    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

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

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

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

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

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

    A1

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

    z

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

    op

    a binary operator that must be associative

    returns

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

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

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

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

    Note: will not terminate for infinite-sized collections.

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

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

    where x1, ..., xn are the elements of this sequence.

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

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

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

    Note: will not terminate for infinite-sized collections.

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

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

    where x1, ..., xn are the elements of this sequence.

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

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

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

    Note: may not terminate for infinite-sized collections.

    p

    the predicate used to test elements.

    returns

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

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

    [use case]

    [use case]
    f

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLikeTraversableOnceGenTraversableOnceFilterMonadic
  51. final def getClass(): Class[_]

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

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

    The nature of the representation is platform dependent.

    returns

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

    Definition Classes
    AnyRef → Any
    Note

    not specified by SLS as a member of AnyRef

  52. def groupBy[K](f: (A) ⇒ K): Map[K, Repr]

    Partitions this sequence into a map of sequences according to some discriminator function.

    Partitions this sequence into a map of sequences 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 sequence.

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

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

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

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

    Definition Classes
    TraversableLikeGenTraversableLike
  53. def grouped(size: Int): Iterator[Repr]

    Partitions elements in fixed size sequences.

    Partitions elements in fixed size sequences.

    size

    the number of elements per group

    returns

    An iterator producing sequences of size size, except the last will be truncated if the elements don't divide evenly.

    Definition Classes
    IterableLike
    See also

    Iterator#grouped

  54. def hasDefiniteSize: Boolean

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

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

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

    returns

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

    Definition Classes
    TraversableLikeTraversableOnceGenTraversableOnce
  55. def hashCode(): Int

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

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

    returns

    the hash code value for this object.

    Definition Classes
    GenSeqLike → AnyRef → Any
  56. def head: A

    Selects the first element of this sequence.

    Selects the first element of this sequence.

    returns

    the first element of this sequence.

    Definition Classes
    IterableLikeGenIterableLikeTraversableLikeGenTraversableLike
    Exceptions thrown
    `NoSuchElementException`

    if the sequence is empty.

  57. def headOption: Option[A]

    Optionally selects the first element.

    Optionally selects the first element.

    returns

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

    Definition Classes
    TraversableLike
  58. def indexOf(elem: A, from: Int): Int

    [use case]

    [use case]
    elem

    the element value to search for.

    from

    the start index

    returns

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

    Definition Classes
    GenSeqLike
  59. def indexOf(elem: A): Int

    [use case]

    [use case]
    elem

    the element value to search for.

    returns

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

    Definition Classes
    GenSeqLike
  60. 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.

  61. 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.

  62. 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
  63. 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 sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    GenSeqLike
  64. 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.

  65. def init: Repr

    Selects all elements except the last.

    Selects all elements except the last.

    returns

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

    Definition Classes
    TraversableLike
    Exceptions thrown
    `UnsupportedOperationException`

    if the sequence is empty.

  66. def inits: Iterator[Repr]

    Iterates over the inits of this sequence.

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

    returns

    an iterator over all the inits of this sequence

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

  67. def intersect(that: Seq[A]): Seq[A]

    [use case]

    [use case]
    that

    the sequence of elements to intersect with.

    returns

    a new collection of type That which contains all elements of this 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
  68. def isDefinedAt(idx: Int): Boolean

    Tests whether this sequence contains given index.

    Tests whether this 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 sequence contains an element at position idx, false otherwise.

    Definition Classes
    GenSeqLike
  69. def isEmpty: Boolean

    Tests whether the sequence is empty.

    Tests whether the sequence is empty.

    returns

    true if the sequence contains no elements, false otherwise.

    Definition Classes
    IterableLikeGenIterableLikeTraversableLikeTraversableOnceGenTraversableOnce
  70. final def isInstanceOf[T0]: Boolean

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

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

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

    returns

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

    Definition Classes
    Any
  71. final def isTraversableAgain: Boolean

    Tests whether this sequence can be repeatedly traversed.

    Tests whether this sequence can be repeatedly traversed.

    returns

    true

    Definition Classes
    GenTraversableLikeGenTraversableOnce
  72. def last: A

    Selects the last element.

    Selects the last element.

    returns

    The last element of this sequence.

    Definition Classes
    TraversableLike
    Exceptions thrown
    NoSuchElementException

    If the sequence is empty.

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

    [use case]

    [use case]
    elem

    the element value to search for.

    end

    the end index.

    returns

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

    Definition Classes
    GenSeqLike
  74. def lastIndexOf(elem: A): Int

    [use case]

    [use case]
    elem

    the element value to search for.

    returns

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

    Definition Classes
    GenSeqLike
  75. 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.

  76. 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.

  77. 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
  78. 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 sequence that satisfies the predicate p, or -1, if none exists.

    Definition Classes
    GenSeqLike
  79. def lastOption: Option[A]

    Optionally selects the last element.

    Optionally selects the last element.

    returns

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

    Definition Classes
    TraversableLike
  80. 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.

  81. def map[B](f: (A) ⇒ B): Seq[B]

    [use case]

    [use case]
    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLikeFilterMonadic
  82. def max: A

    [use case]

    [use case]
    returns

    the largest element of this sequence with respect to the ordering cmp.

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  84. def min: A

    [use case]

    [use case]
    returns

    the smallest element of this sequence with respect to the ordering cmp.

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  86. def mkString: String

    Displays all elements of this sequence in a string.

    Displays all elements of this sequence in a string.

    returns

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

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

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

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

    sep

    the separator string.

    returns

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

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

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

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

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

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

  89. final def ne(arg0: AnyRef): Boolean

    Equivalent to !(this eq that).

    Equivalent to !(this eq that).

    returns

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

    Definition Classes
    AnyRef
  90. def nonEmpty: Boolean

    Tests whether the sequence is not empty.

    Tests whether the sequence is not empty.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  91. final def notify(): Unit

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

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

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  92. final def notifyAll(): Unit

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

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

    Definition Classes
    AnyRef
    Note

    not specified by SLS as a member of AnyRef

  93. def padTo(len: Int, elem: A): Seq[A]

    [use case]

    [use case]
    len

    the target length

    elem

    the padding value

    returns

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

    Definition Classes
    SeqLikeGenSeqLike
  94. 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
  95. def parCombiner: Combiner[A, ParSeq[A]]

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

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

    returns

    a combiner for the parallel collection of type ParRepr

    Attributes
    protected[this]
    Definition Classes
    SeqLikeTraversableLikeParallelizable
  96. def partition(p: (A) ⇒ Boolean): (Repr, Repr)

    Partitions this sequence in two sequences according to a predicate.

    Partitions this sequence in two sequences according to a predicate.

    p

    the predicate on which to partition.

    returns

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

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

    [use case]

    [use case]
    from

    the index of the first replaced element

    replaced

    the number of elements to drop in the original sequence

    returns

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

    Definition Classes
    SeqLikeGenSeqLike
  98. def permutations: Iterator[Repr]

    Iterates over distinct permutations.

    Iterates over distinct permutations.

    returns

    An Iterator which traverses the distinct permutations of this sequence.

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

  99. 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 sequence such that every element of the segment satisfies the predicate p.

    Definition Classes
    GenSeqLike
  100. def product: A

    [use case]

    [use case]
    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  101. def reduce[A1 >: A](op: (A1, A1) ⇒ A1): A1

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

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

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

    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 sequence is nonempty.

    Definition Classes
    TraversableOnceGenTraversableOnce
    Exceptions thrown
    UnsupportedOperationException

    if this sequence is empty.

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

    Definition Classes
    TraversableOnce
  103. def reduceLeftOption[B >: A](op: (B, A) ⇒ B): Option[B]

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

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

    Note: will not terminate for infinite-sized collections.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    an option value containing the result of reduceLeft(op) is this sequence is nonempty, None otherwise.

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

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

    Reduces the elements of this sequence, 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
  105. def reduceRight[B >: A](op: (A, B) ⇒ B): B

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

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

    Note: will not terminate for infinite-sized collections.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this sequence, going right to left:

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

    where x1, ..., xn are the elements of this sequence.

    Definition Classes
    IterableLikeTraversableOnceGenTraversableOnce
    Exceptions thrown
    `UnsupportedOperationException`

    if this sequence is empty.

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

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

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

    Note: will not terminate for infinite-sized collections.

    B

    the result type of the binary operator.

    op

    the binary operator.

    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  107. def repr: Repr

    The collection of type sequence underlying this TraversableLike object.

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

    Definition Classes
    TraversableLikeGenTraversableLike
  108. def reverse: Repr

    Returns new sequence wih elements in reversed order.

    Returns new sequence wih 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
  109. 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

  110. def reverseMap[B](f: (A) ⇒ B): Seq[B]

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

    [use case]

    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 collection of type That resulting from applying the given function f to each element of this sequence and collecting the results in reversed order.

    Definition Classes
    SeqLikeGenSeqLike
  111. def reversed: List[A]

    Attributes
    protected[this]
    Definition Classes
    TraversableOnce
  112. def sameElements(that: GenIterable[A]): Boolean

    [use case]

    [use case]
    that

    the collection to compare with.

    returns

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

    Definition Classes
    IterableLikeGenIterableLike
  113. def scan[B >: A, That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Repr, B, That]): That

    Computes a prefix scan of the elements of the collection.

    Computes a prefix scan of the elements of the collection.

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

    B

    element type of the resulting collection

    That

    type of the resulting collection

    z

    neutral element for the operator op

    op

    the associative operator for the scan

    cbf

    combiner factory which provides a combiner

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  114. def scanLeft[B, That](z: B)(op: (B, A) ⇒ B)(implicit bf: CanBuildFrom[Repr, B, That]): That

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

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

    Note: will not terminate for infinite-sized collections.

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

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

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

    Note: will not terminate for infinite-sized collections.

    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.

  116. 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
  117. 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
  118. def slice(from: Int, until: Int): Repr

    Selects an interval of elements.

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

       from <= indexOf(x) < until
    
    from

    the lowest index to include from this sequence.

    until

    the highest index to EXCLUDE from this sequence.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  119. def sliding(size: Int, step: Int): Iterator[Repr]

    Definition Classes
    IterableLike
  120. def sliding(size: Int): Iterator[Repr]

    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

    returns

    An iterator producing sequences of size size, except the last and the only element will be truncated if there are fewer elements than size.

    Definition Classes
    IterableLike
    See also

    Iterator#sliding

  121. def sortBy[B](f: (A) ⇒ B)(implicit ord: Ordering[B]): Repr

    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)).

    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.

  122. def sortWith(lt: (A, A) ⇒ Boolean): Repr

    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 wrt 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.

    Example:
    1.    List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) =
         List("Bob", "John", "Steve", "Tom")
      
  123. def sorted[B >: A](implicit ord: Ordering[B]): Repr

    Sorts this sequence according to an Ordering.

    Sorts this sequence according to an Ordering.

    The sort is stable. That is, elements that are equal wrt 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.

    See also

    scala.math.Ordering

  124. def span(p: (A) ⇒ Boolean): (Repr, Repr)

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

    Splits this sequence 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.

    p

    the test predicate

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
  125. def splitAt(n: Int): (Repr, Repr)

    Splits this sequence into two at a given position.

    Splits this sequence into two at a given position. Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n).

    n

    the position at which to split.

    returns

    a pair of sequences consisting of the first n elements of this sequence, and the other elements.

    Definition Classes
    TraversableLikeGenTraversableLike
  126. 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
  127. def startsWith[B](that: GenSeq[B]): Boolean

    Tests whether this sequence starts with the given sequence.

    Tests whether this 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
  128. 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 sequence. By default the string prefix is the simple name of the collection class sequence.

    Definition Classes
    TraversableLikeGenTraversableLike
  129. def sum: A

    [use case]

    [use case]
    returns

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

    Definition Classes
    TraversableOnceGenTraversableOnce
  130. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  131. def tail: Repr

    Selects all elements except the first.

    Selects all elements except the first.

    returns

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

    Definition Classes
    TraversableLikeGenTraversableLike
    Exceptions thrown
    `UnsupportedOperationException`

    if the sequence is empty.

  132. def tails: Iterator[Repr]

    Iterates over the tails of this sequence.

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

    returns

    an iterator over all the tails of this sequence

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

  133. def take(n: Int): Repr

    Selects first n elements.

    Selects first n elements.

    n

    Tt number of elements to take from this sequence.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  134. def takeRight(n: Int): Repr

    Selects last n elements.

    Selects last n elements.

    n

    the number of elements to take

    returns

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

    Definition Classes
    IterableLike
  135. def takeWhile(p: (A) ⇒ Boolean): Repr

    Takes longest prefix of elements that satisfy a predicate.

    Takes longest prefix of elements that satisfy a predicate.

    p

    The predicate used to test elements.

    returns

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

    Definition Classes
    IterableLikeTraversableLikeGenTraversableLike
  136. def thisCollection: Seq[A]

    The underlying collection seen as an instance of Seq.

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

    Attributes
    protected[this]
    Definition Classes
    SeqLikeIterableLikeTraversableLike
  137. def toArray: Array[A]

    [use case]

    [use case]
    returns

    an array containing all elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  138. def toBuffer[B >: A]: Buffer[B]

    Converts this sequence to a mutable buffer.

    Converts this sequence to a mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  139. def toCollection(repr: Repr): Seq[A]

    A conversion from collections of type Repr to Seq objects.

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

    Attributes
    protected[this]
    Definition Classes
    SeqLikeIterableLikeTraversableLike
  140. def toIndexedSeq: IndexedSeq[A]

    Converts this sequence to an indexed sequence.

    Converts this sequence to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

    an indexed sequence containing all elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  141. def toIterable: Iterable[A]

    Converts this sequence to an iterable collection.

    Converts this sequence to an iterable collection. Note that the choice of target Iterable is lazy in this default implementation as this TraversableOnce may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterable containing all elements of this sequence.

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

    Returns an Iterator over the elements in this sequence.

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

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterator containing all elements of this sequence.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableOnce
  143. def toList: List[A]

    Converts this sequence to a list.

    Converts this sequence to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this sequence.

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

    [use case]

    [use case]
    returns

    a map containing all elements of this sequence.

    Definition Classes
    TraversableOnceGenTraversableOnce
  145. def toSeq: Seq[A]

    Converts this sequence to a sequence.

    Converts this sequence to a sequence.

    Note: will not terminate for infinite-sized collections.

    Overridden for efficiency.

    returns

    a sequence containing all elements of this sequence.

    Definition Classes
    SeqLikeGenSeqLikeTraversableOnceGenTraversableOnce
  146. def toSet[B >: A]: Set[B]

    Converts this sequence to a set.

    Converts this sequence to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this sequence.

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

    Converts this sequence to a stream.

    Converts this sequence to a stream.

    Note: will not terminate for infinite-sized collections.

    returns

    a stream containing all elements of this sequence.

    Definition Classes
    IterableLikeTraversableLikeGenTraversableOnce
  148. 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
    SeqLikeTraversableLike → AnyRef → Any
  149. def toTraversable: Traversable[A]

    Converts this sequence to an unspecified Traversable.

    Converts this sequence 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 sequence.

    Definition Classes
    TraversableLikeTraversableOnceGenTraversableOnce
  150. def union(that: Seq[A]): Seq[A]

    [use case]

    [use case]
    that

    the sequence to add.

    returns

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

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

    [use case]

    [use case]
    index

    the position of the replacement

    elem

    the replacing element

    returns

    a new sequence which is a copy of this sequence with the element at position index replaced by elem.

    Definition Classes
    SeqLikeGenSeqLike
  152. def view(from: Int, until: Int): SeqView[A, Repr]

    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
  153. def view: SeqView[A, Repr]

    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
  154. final def wait(): Unit

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

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

    Definition Classes
    AnyRef
    Annotations
    @throws()
  157. def withFilter(p: (A) ⇒ Boolean): FilterMonadic[A, Repr]

    Creates a non-strict filter of this sequence.

    Creates a non-strict filter of this sequence.

    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.

    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 sequence which satisfy the predicate p.

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

    [use case]

    [use case]
    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 collection of type That containing pairs consisting of corresponding elements of this sequence and that. The length of the returned collection is the minimum of the lengths of this sequence and that.

    Definition Classes
    IterableLikeGenIterableLike
  159. def zipAll[B](that: Iterable[B], thisElem: A, thatElem: B): Seq[(A, B)]

    [use case]

    [use case]
    that

    the iterable providing the second half of each result pair

    thisElem

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

    thatElem

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

    returns

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

    Definition Classes
    IterableLikeGenIterableLike
  160. def zipWithIndex: Seq[(A, Int)]

    [use case]

    [use case]
    returns

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

    Definition Classes
    IterableLikeGenIterableLike

Inherited from GenSeqLike[A, Repr]

Inherited from IterableLike[A, Repr]

Inherited from GenIterableLike[A, Repr]

Inherited from TraversableLike[A, Repr]

Inherited from GenTraversableLike[A, Repr]

Inherited from Parallelizable[A, ParSeq[A]]

Inherited from TraversableOnce[A]

Inherited from GenTraversableOnce[A]

Inherited from FilterMonadic[A, Repr]

Inherited from HasNewBuilder[A, Repr]

Inherited from Equals

Inherited from AnyRef

Inherited from Any