Ordering

scala.math.Ordering

See theOrdering companion trait

object Ordering extends LowPriorityOrderingImplicits

This is the companion object for the scala.math.Ordering trait.

It contains many implicit orderings as well as well as methods to construct new orderings.

Attributes

Companion: trait
Source: Ordering.scala
Graph
Supertypes: trait Serializable

trait LowPriorityOrderingImplicits

class Object

trait Matchable

class Any
Self type: Ordering.type

Members list

Type members

Classlikes

Attributes

Source: Ordering.scala
Supertypes: trait BigDecimalOrdering

trait Ordering[BigDecimal]

trait PartialOrdering[BigDecimal]

trait Equiv[BigDecimal]

trait Serializable

trait Comparator[BigDecimal]

class Object

trait Matchable

class Any
Show all
Self type: BigDecimal.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[BigDecimal]

trait PartialOrdering[BigDecimal]

trait Equiv[BigDecimal]

trait Serializable

trait Comparator[BigDecimal]

class Object

trait Matchable

class Any
Show all
Known subtypes: object BigDecimalAsIfIntegral

object BigDecimalIsFractional

object BigDecimal

Attributes

Source: Ordering.scala
Supertypes: trait BigIntOrdering

trait Ordering[BigInt]

trait PartialOrdering[BigInt]

trait Equiv[BigInt]

trait Serializable

trait Comparator[BigInt]

class Object

trait Matchable

class Any
Show all
Self type: BigInt.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[BigInt]

trait PartialOrdering[BigInt]

trait Equiv[BigInt]

trait Serializable

trait Comparator[BigInt]

class Object

trait Matchable

class Any
Show all
Known subtypes: object BigIntIsIntegral

object BigInt

Attributes

Source: Ordering.scala
Supertypes: trait BooleanOrdering

trait Ordering[Boolean]

trait PartialOrdering[Boolean]

trait Equiv[Boolean]

trait Serializable

trait Comparator[Boolean]

class Object

trait Matchable

class Any
Show all
Self type: Boolean.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Boolean]

trait PartialOrdering[Boolean]

trait Equiv[Boolean]

trait Serializable

trait Comparator[Boolean]

class Object

trait Matchable

class Any
Show all
Known subtypes: object Boolean

Attributes

Source: Ordering.scala
Supertypes: trait ByteOrdering

trait Ordering[Byte]

trait PartialOrdering[Byte]

trait Equiv[Byte]

trait Serializable

trait Comparator[Byte]

class Object

trait Matchable

class Any
Show all
Self type: Byte.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Byte]

trait PartialOrdering[Byte]

trait Equiv[Byte]

trait Serializable

trait Comparator[Byte]

class Object

trait Matchable

class Any
Show all
Known subtypes: object ByteIsIntegral

object Byte

An ordering which caches the value of its reverse.

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[T]

trait PartialOrdering[T]

trait Equiv[T]

trait Serializable

trait Comparator[T]

class Object

trait Matchable

class Any
Show all
Known subtypes: object Int

Attributes

Source: Ordering.scala
Supertypes: trait CharOrdering

trait Ordering[Char]

trait PartialOrdering[Char]

trait Equiv[Char]

trait Serializable

trait Comparator[Char]

class Object

trait Matchable

class Any
Show all
Self type: Char.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Char]

trait PartialOrdering[Char]

trait Equiv[Char]

trait Serializable

trait Comparator[Char]

class Object

trait Matchable

class Any
Show all
Known subtypes: object CharIsIntegral

object Char

Attributes

Source: Ordering.scala
Supertypes: trait TotalOrdering

trait Ordering[Double]

trait PartialOrdering[Double]

trait Equiv[Double]

trait Serializable

trait Comparator[Double]

class Object

trait Matchable

class Any
Show all
Self type: DeprecatedDoubleOrdering.type

Attributes

Source: Ordering.scala
Supertypes: trait TotalOrdering

trait Ordering[Float]

trait PartialOrdering[Float]

trait Equiv[Float]

trait Serializable

trait Comparator[Float]

class Object

trait Matchable

class Any
Show all
Self type: DeprecatedFloatOrdering.type

Orderings for Doubles.

The behavior of the comparison operations provided by the default (implicit) ordering on Double changed in 2.10.0 and 2.13.0. Prior to Scala 2.10.0, the Ordering instance used semantics consistent with java.lang.Double.compare.

Scala 2.10.0 changed the implementation of lt, equiv, min, etc., to be IEEE 754 compliant, while keeping the compare method NOT compliant, creating an internally inconsistent instance. IEEE 754 specifies that 0.0 == -0.0. In addition, it requires all comparisons with Double.NaN return false thus 0.0 < Double.NaN, 0.0 > Double.NaN, and Double.NaN == Double.NaN all yield false, analogous None in flatMap.

Recognizing the limitation of the IEEE 754 semantics in terms of ordering, Scala 2.13.0 created two instances: Ordering.Double.IeeeOrdering, which retains the IEEE 754 semantics from Scala 2.12.x, and Ordering.Double.TotalOrdering, which brings back the java.lang.Double.compare semantics for all operations. The default extends TotalOrdering.

List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).sorted      // List(-Infinity, 0.0, 1.0, NaN)
List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).min         // -Infinity
implicitly[Ordering[Double]].lt(0.0, 0.0 / 0.0)   // true
{
  import Ordering.Double.IeeeOrdering
  List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).sorted    // List(-Infinity, 0.0, 1.0, NaN)
  List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).min       // NaN
  implicitly[Ordering[Double]].lt(0.0, 0.0 / 0.0) // false
}

Attributes

Source: Ordering.scala
Supertypes: class Object

trait Matchable

class Any
Self type: Double.type

Attributes

Source: Ordering.scala
Supertypes: class Object

trait Matchable

class Any
Known subtypes: object Implicits

Orderings for Floats.

The behavior of the comparison operations provided by the default (implicit) ordering on Float changed in 2.10.0 and 2.13.0. Prior to Scala 2.10.0, the Ordering instance used semantics consistent with java.lang.Float.compare.

Scala 2.10.0 changed the implementation of lt, equiv, min, etc., to be IEEE 754 compliant, while keeping the compare method NOT compliant, creating an internally inconsistent instance. IEEE 754 specifies that 0.0F == -0.0F. In addition, it requires all comparisons with Float.NaN return false thus 0.0F < Float.NaN, 0.0F > Float.NaN, and Float.NaN == Float.NaN all yield false, analogous None in flatMap.

Recognizing the limitation of the IEEE 754 semantics in terms of ordering, Scala 2.13.0 created two instances: Ordering.Float.IeeeOrdering, which retains the IEEE 754 semantics from Scala 2.12.x, and Ordering.Float.TotalOrdering, which brings back the java.lang.Float.compare semantics for all operations. The default extends TotalOrdering.

List(0.0F, 1.0F, 0.0F / 0.0F, -1.0F / 0.0F).sorted      // List(-Infinity, 0.0, 1.0, NaN)
List(0.0F, 1.0F, 0.0F / 0.0F, -1.0F / 0.0F).min         // -Infinity
implicitly[Ordering[Float]].lt(0.0F, 0.0F / 0.0F)       // true
{
  import Ordering.Float.IeeeOrdering
  List(0.0F, 1.0F, 0.0F / 0.0F, -1.0F / 0.0F).sorted    // List(-Infinity, 0.0, 1.0, NaN)
  List(0.0F, 1.0F, 0.0F / 0.0F, -1.0F / 0.0F).min       // NaN
  implicitly[Ordering[Float]].lt(0.0F, 0.0F / 0.0F)     // false
}

Attributes

Source: Ordering.scala
Supertypes: class Object

trait Matchable

class Any
Self type: Float.type

An object containing implicits which are not in the default scope.

Attributes

Source: Ordering.scala
Supertypes: trait ExtraImplicits

class Object

trait Matchable

class Any
Self type: Implicits.type

Attributes

Source: Ordering.scala
Supertypes: trait CachedReverse[Int]

trait IntOrdering

trait Ordering[Int]

trait PartialOrdering[Int]

trait Equiv[Int]

trait Serializable

trait Comparator[Int]

class Object

trait Matchable

class Any
Show all
Self type: Int.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Int]

trait PartialOrdering[Int]

trait Equiv[Int]

trait Serializable

trait Comparator[Int]

class Object

trait Matchable

class Any
Show all
Known subtypes: object IntIsIntegral

object Int

Attributes

Source: Ordering.scala
Supertypes: trait LongOrdering

trait Ordering[Long]

trait PartialOrdering[Long]

trait Equiv[Long]

trait Serializable

trait Comparator[Long]

class Object

trait Matchable

class Any
Show all
Self type: Long.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Long]

trait PartialOrdering[Long]

trait Equiv[Long]

trait Serializable

trait Comparator[Long]

class Object

trait Matchable

class Any
Show all
Known subtypes: object LongIsIntegral

object Long

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Option[T]]

trait PartialOrdering[Option[T]]

trait Equiv[Option[T]]

trait Serializable

trait Comparator[Option[T]]

class Object

trait Matchable

class Any
Show all

Attributes

Source: Ordering.scala
Supertypes: trait ShortOrdering

trait Ordering[Short]

trait PartialOrdering[Short]

trait Equiv[Short]

trait Serializable

trait Comparator[Short]

class Object

trait Matchable

class Any
Show all
Self type: Short.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Short]

trait PartialOrdering[Short]

trait Equiv[Short]

trait Serializable

trait Comparator[Short]

class Object

trait Matchable

class Any
Show all
Known subtypes: object ShortIsIntegral

object Short

Attributes

Source: Ordering.scala
Supertypes: trait StringOrdering

trait Ordering[String]

trait PartialOrdering[String]

trait Equiv[String]

trait Serializable

trait Comparator[String]

class Object

trait Matchable

class Any
Show all
Self type: String.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[String]

trait PartialOrdering[String]

trait Equiv[String]

trait Serializable

trait Comparator[String]

class Object

trait Matchable

class Any
Show all
Known subtypes: object String

Attributes

Source: Ordering.scala
Supertypes: trait SymbolOrdering

trait Ordering[Symbol]

trait PartialOrdering[Symbol]

trait Equiv[Symbol]

trait Serializable

trait Comparator[Symbol]

class Object

trait Matchable

class Any
Show all
Self type: Symbol.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Symbol]

trait PartialOrdering[Symbol]

trait Equiv[Symbol]

trait Serializable

trait Comparator[Symbol]

class Object

trait Matchable

class Any
Show all
Known subtypes: object Symbol

Attributes

Source: Ordering.scala
Supertypes: trait UnitOrdering

trait Ordering[Unit]

trait PartialOrdering[Unit]

trait Equiv[Unit]

trait Serializable

trait Comparator[Unit]

class Object

trait Matchable

class Any
Show all
Self type: Unit.type

Attributes

Source: Ordering.scala
Supertypes: trait Ordering[Unit]

trait PartialOrdering[Unit]

trait Equiv[Unit]

trait Serializable

trait Comparator[Unit]

class Object

trait Matchable

class Any
Show all
Known subtypes: object Unit

Inherited types

Attributes

Inherited from:: LowPriorityOrderingImplicits
Source: Ordering.scala

Value members

Concrete methods

Attributes

Source: Ordering.scala

Given f, a function from T into S, creates an Ordering[T] whose compare function is equivalent to:

def compare(x:T, y:T) = Ordering[S].compare(f(x), f(y))

This function is an analogue to Ordering.on where the Ordering[S] parameter is passed implicitly.

Attributes

Source: Ordering.scala

Construct an Ordering[T] given a function lt.

Attributes

Source: Ordering.scala

Implicits

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Attributes

Source: Ordering.scala

Deprecated implicits

Attributes

Deprecated: [Since version 2.13.0]
Iterables are not guaranteed to have a consistent order, so the Ordering returned by this method may not be stable or meaningful. If you are using a type with a consistent order (such as Seq), use its Ordering (found in the Implicits object) instead.
Source: Ordering.scala

Inherited implicits

Attributes

Inherited from:: LowPriorityOrderingImplicits
Source: Ordering.scala

This would conflict with all the nice implicit Orderings available, but thanks to the magic of prioritized implicits via subclassing we can make Ordered[A] => Ordering[A] only turn up if nothing else works. Since Ordered[A] extends Comparable[A] anyway, we can throw in some Java interop too.

Attributes

Inherited from:: LowPriorityOrderingImplicits
Source: Ordering.scala

In this article

Generated with