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 Searching

    A collection of wrappers that provide sequence classes with search functionality.

    A collection of wrappers that provide sequence classes with search functionality.

    Example usage:

    import scala.collection.Searching._
val l = List(1, 2, 3, 4, 5)
l.search(3)
// == Found(2)
    Definition Classes
    collection
  • Found
  • InsertionPoint
  • SearchImpl
  • SearchResult

case class Found(foundIndex: Int) extends SearchResult with Product with Serializable

Source
Searching.scala
Linear Supertypes
Serializable, java.io.Serializable, Product, Equals, SearchResult, AnyRef, Any
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. Found
  2. Serializable
  3. Serializable
  4. Product
  5. Equals
  6. SearchResult
  7. AnyRef
  8. Any
Implicitly
  1. by search
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
  1. Hide All
  2. Show All
Visibility
  1. Public
  2. All

Instance Constructors

  1. new Found(foundIndex: Int)

Value Members

  1. val coll: SeqLike[A, Found]
    Implicit
    This member is added by an implicit conversion from Found to SearchImpl[A, Found] performed by method search in scala.collection.Searching. This conversion will take place only if an implicit value of type IsSeqLike[Found] is in scope.
    Definition Classes
    SearchImpl
  2. val foundIndex: Int
  3. def insertionPoint: Int
    Definition Classes
    Found → SearchResult
  4. final def search[B >: A](elem: B, from: Int, to: Int)(implicit ord: math.Ordering[B]): SearchResult

    Search within an interval in the sorted sequence for a specific element.

    Search within an interval in the sorted sequence for a specific element. If the sequence is an IndexedSeqLike, a binary search is used. Otherwise, a linear search is used.

    The sequence should be sorted with the same Ordering before calling; otherwise, the results are undefined.

    elem

    the element to find.

    from

    the index where the search starts.

    to

    the index following where the search ends.

    ord

    the ordering to be used to compare elements.

    returns

    a Found value containing the index corresponding to the element in the sequence, or the InsertionPoint where the element would be inserted if the element is not in the sequence.

    Implicit
    This member is added by an implicit conversion from Found to SearchImpl[A, Found] performed by method search in scala.collection.Searching. This conversion will take place only if an implicit value of type IsSeqLike[Found] is in scope.
    Definition Classes
    SearchImpl
    See also

    scala.collection.IndexedSeqLike

    scala.math.Ordering

    scala.collection.SeqLike, method sorted

  5. final def search[B >: A](elem: B)(implicit ord: math.Ordering[B]): SearchResult

    Search the sorted sequence for a specific element.

    Search the sorted sequence for a specific element. If the sequence is an IndexedSeqLike, a binary search is used. Otherwise, a linear search is used.

    The sequence should be sorted with the same Ordering before calling; otherwise, the results are undefined.

    elem

    the element to find.

    ord

    the ordering to be used to compare elements.

    returns

    a Found value containing the index corresponding to the element in the sequence, or the InsertionPoint where the element would be inserted if the element is not in the sequence.

    Implicit
    This member is added by an implicit conversion from Found to SearchImpl[A, Found] performed by method search in scala.collection.Searching. This conversion will take place only if an implicit value of type IsSeqLike[Found] is in scope.
    Definition Classes
    SearchImpl
    See also

    scala.collection.IndexedSeqLike

    scala.math.Ordering

    scala.collection.SeqLike, method sorted