Packages

  • package root

    This is the documentation for the Scala standard library.

    This is the documentation for the Scala standard library.

    Package structure

    The scala package contains core types like Int, Float, Array or Option which are accessible in all Scala compilation units without explicit qualification or imports.

    Notable packages include:

    Other packages exist. See the complete list on the right.

    Additional parts of the standard library are shipped as separate libraries. These include:

    • scala.reflect - Scala's reflection API (scala-reflect.jar)
    • scala.xml - XML parsing, manipulation, and serialization (scala-xml.jar)
    • scala.swing - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
    • scala.util.parsing - Parser combinators (scala-parser-combinators.jar)

    Automatic imports

    Identifiers in the scala package and the scala.Predef object are always in scope by default.

    Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, List is an alias for scala.collection.immutable.List.

    Other aliases refer to classes provided by the underlying platform. For example, on the JVM, String is an alias for java.lang.String.

    Definition Classes
    root
  • package scala

    Core Scala types.

    Core Scala types. They are always available without an explicit import.

    Definition Classes
    root
  • package collection

    Contains the base traits and objects needed to use and extend Scala's collection library.

    Contains the base traits and objects needed to use and extend Scala's collection library.

    Guide

    A detailed guide for using the collections library is available at http://docs.scala-lang.org/overviews/collections/introduction.html. Developers looking to extend the collections library can find a description of its architecture at http://docs.scala-lang.org/overviews/core/architecture-of-scala-collections.html.

    Using Collections

    It is convenient to treat all collections as either a scala.collection.Traversable or scala.collection.Iterable, as these traits define the vast majority of operations on a collection.

    Collections can, of course, be treated as specifically as needed, and the library is designed to ensure that the methods that transform collections will return a collection of the same type: 

    scala> val array = Array(1,2,3,4,5,6)
array: Array[Int] = Array(1, 2, 3, 4, 5, 6)

scala> array map { _.toString }
res0: Array[String] = Array(1, 2, 3, 4, 5, 6)

scala> val list = List(1,2,3,4,5,6)
list: List[Int] = List(1, 2, 3, 4, 5, 6)

scala> list map { _.toString }
res1: List[String] = List(1, 2, 3, 4, 5, 6)

    Creating Collections

    The most common way to create a collection is to use its companion object as a factory. The three most commonly used collections are scala.collection.Seq, scala.collection.immutable.Set, and scala.collection.immutable.Map. They can be used directly as shown below since their companion objects are all available as type aliases in either the scala package or in scala.Predef. New collections are created like this:

    scala> val seq = Seq(1,2,3,4,1)
seq: Seq[Int] = List(1, 2, 3, 4, 1)

scala> val set = Set(1,2,3,4,1)
set: scala.collection.immutable.Set[Int] = Set(1, 2, 3, 4)

scala> val map = Map(1 -> "one", 2 -> "two", 3 -> "three", 2 -> "too")
map: scala.collection.immutable.Map[Int,String] = Map(1 -> one, 2 -> too, 3 -> three)

    It is also typical to prefer the scala.collection.immutable collections over those in scala.collection.mutable; the types aliased in the scala.Predef object are the immutable versions.

    Also note that the collections library was carefully designed to include several implementations of each of the three basic collection types. These implementations have specific performance characteristics which are described in the guide.

    The concrete parallel collections also have specific performance characteristics which are described in the parallel collections guide

    Converting to and from Java Collections

    The scala.collection.JavaConverters object provides a collection of decorators that allow converting between Scala and Java collections using asScala and asJava methods.

    Definition Classes
    scala
  • object TraversableView

    An object containing the necessary implicit definitions to make TraversableViews work.

    An object containing the necessary implicit definitions to make TraversableViews work. Its definitions are generally not accessed directly by clients.

    Definition Classes
    collection
  • NoBuilder

class NoBuilder[A] extends Builder[A, Nothing]

Source
TraversableView.scala
Linear Supertypes
Builder[A, Nothing], Growable[A], Clearable, AnyRef, Any
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. NoBuilder
  2. Builder
  3. Growable
  4. Clearable
  5. AnyRef
  6. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
  1. Hide All
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Visibility
  1. Public
  2. All

Instance Constructors

  1. new NoBuilder()

Value Members

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

    Test two objects for inequality.

    Test two objects for inequality.

    returns

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

    Definition Classes
    AnyRef → Any
  2. 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
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to any2stringadd[NoBuilder[A]] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ++=(xs: TraversableOnce[A]): NoBuilder.this.type

    adds all elements produced by a TraversableOnce to this growable collection.

    adds all elements produced by a TraversableOnce to this growable collection.

    xs

    the TraversableOnce producing the elements to add.

    returns

    the growable collection itself.

    Definition Classes
    Growable
  5. def +=(elem: A): NoBuilder.this.type

    Adds a single element to the builder.

    Adds a single element to the builder.

    elem

    the element to be added.

    returns

    the builder itself.

    Definition Classes
    NoBuilder → Builder → Growable
  6. def +=(elem1: A, elem2: A, elems: A*): NoBuilder.this.type

    adds two or more elements to this growable collection.

    adds two or more elements to this growable collection.

    elem1

    the first element to add.

    elem2

    the second element to add.

    elems

    the remaining elements to add.

    returns

    the growable collection itself

    Definition Classes
    Growable
  7. def ->[B](y: B): (NoBuilder[A], B)
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to ArrowAssoc[NoBuilder[A]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  8. final def ==(arg0: Any): Boolean

    The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    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
    AnyRef → Any
  9. final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type T0.

    Cast the receiver object to be of type T0.

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

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

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

  10. def clear(): Unit

    Clears the contents of this builder.

    Clears the contents of this builder. After execution of this method the builder will contain no elements.

    Definition Classes
    NoBuilder → Builder → Growable → Clearable
  11. 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( ... ) @native()
    Note

    not specified by SLS as a member of AnyRef

  12. def ensuring(cond: (NoBuilder[A]) ⇒ Boolean, msg: ⇒ Any): NoBuilder[A]
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to Ensuring[NoBuilder[A]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: (NoBuilder[A]) ⇒ Boolean): NoBuilder[A]
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to Ensuring[NoBuilder[A]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: Boolean, msg: ⇒ Any): NoBuilder[A]
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to Ensuring[NoBuilder[A]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: Boolean): NoBuilder[A]
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to Ensuring[NoBuilder[A]] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. final def eq(arg0: AnyRef): Boolean

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

    Tests whether the argument (that) 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
  17. def equals(arg0: Any): Boolean

    The equality method for reference types.

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

    See also equals in scala.Any.

    returns

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

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

    not specified by SLS as a member of AnyRef

  19. final def getClass(): Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  20. def hashCode(): Int

    The hashCode method for reference types.

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

    returns

    the hash code value for this object.

    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  21. 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
  22. def iterator: Iterator[A]
  23. def mapResult[NewTo](f: (Nothing) ⇒ NewTo): Builder[A, NewTo]

    Creates a new builder by applying a transformation function to the results of this builder.

    Creates a new builder by applying a transformation function to the results of this builder.

    NewTo

    the type of collection returned by f.

    f

    the transformation function.

    returns

    a new builder which is the same as the current builder except that a transformation function is applied to this builder's result.

    Definition Classes
    Builder
    Note

    The original builder should no longer be used after mapResult is called.

  24. 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
  25. 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
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  26. 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
    Annotations
    @native()
    Note

    not specified by SLS as a member of AnyRef

  27. def result(): Nothing

    Produces a collection from the added elements.

    Produces a collection from the added elements. This is a terminal operation: the builder's contents are undefined after this operation, and no further methods should be called.

    returns

    a collection containing the elements added to this builder.

    Definition Classes
    NoBuilder → Builder
  28. def sizeHint(coll: TraversableLike[_, _], delta: Int): Unit

    Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta.

    Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

    coll

    the collection which serves as a hint for the result's size.

    delta

    a correction to add to the coll.size to produce the size hint.

    Definition Classes
    Builder
  29. def sizeHint(coll: TraversableLike[_, _]): Unit

    Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta.

    Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method, which is determined by calling sizeHint.

    Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

    coll

    the collection which serves as a hint for the result's size.

    Definition Classes
    Builder
  30. def sizeHint(size: Int): Unit

    Gives a hint how many elements are expected to be added when the next result is called.

    Gives a hint how many elements are expected to be added when the next result is called. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

    size

    the hint how many elements will be added.

    Definition Classes
    Builder
  31. def sizeHintBounded(size: Int, boundingColl: TraversableLike[_, _]): Unit

    Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection.

    Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

    size

    the hint how many elements will be added.

    boundingColl

    the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.

    Definition Classes
    Builder
  32. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  33. def toString(): String

    Creates a String representation of this object.

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

    returns

    a String representation of the object.

    Definition Classes
    AnyRef → Any
  34. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  35. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  36. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  37. def →[B](y: B): (NoBuilder[A], B)
    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to ArrowAssoc[NoBuilder[A]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Deprecated Value Members

  1. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

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

    Implicit
    This member is added by an implicit conversion from NoBuilder[A] to StringFormat[NoBuilder[A]] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

Inherited from Builder[A, Nothing]

Inherited from Growable[A]

Inherited from Clearable

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from NoBuilder[A] to any2stringadd[NoBuilder[A]]

Inherited by implicit conversion StringFormat from NoBuilder[A] to StringFormat[NoBuilder[A]]

Inherited by implicit conversion Ensuring from NoBuilder[A] to Ensuring[NoBuilder[A]]

Inherited by implicit conversion ArrowAssoc from NoBuilder[A] to ArrowAssoc[NoBuilder[A]]

Ungrouped