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Scala 3/scala/scala.math/Ordering/OptionOrdering

OptionOrdering

scala.math.Ordering.OptionOrdering
trait OptionOrdering[T] extends Ordering[Option[T]]

Attributes

Source
Ordering.scala
Graph
Supertypes
trait Ordering[Option[T]]
trait Equiv[Option[T]]
trait Serializable
trait Comparator[Option[T]]
class Object
trait Matchable
class Any
Show all

Members list

Type members

Inherited classlikes

class OrderingOps(lhs: T)

This inner class defines comparison operators available for T.

This inner class defines comparison operators available for T.

It can't extend AnyVal because it is not a top-level class or a member of a statically accessible object.

Attributes

Inherited from:
Ordering
Source
Ordering.scala
Supertypes
class Object
trait Matchable
class Any

Value members

Abstract methods

def optionOrdering: Ordering[T]

Attributes

Source
Ordering.scala

Concrete methods

def compare(x: Option[T], y: Option[T]): Int

Returns an integer whose sign communicates how x compares to y.

Returns an integer whose sign communicates how x compares to y.

The result sign has the following meaning:

- negative if x < y - positive if x > y - zero otherwise (if x == y)

Attributes

Source
Ordering.scala
override def equals(obj: Any): Boolean

Compares the receiver object (this) with the argument object (that) for equivalence.

Compares the receiver object (this) with the argument object (that) for equivalence.

Any implementation of this method should be an equivalence relation:

- It is reflexive: for any instance x of type Any, x.equals(x) should return true. - It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true. - It is transitive: for any instances x, y, and z of type Any if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override hashCode to ensure that objects which are "equal" (o1.equals(o2) returns true) hash to the same scala.Int. (o1.hashCode.equals(o2.hashCode)).

Value parameters

that

the object to compare against this object for equality.

Attributes

Returns

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

Definition Classes
Source
Ordering.scala
override def hashCode(): Int

Calculates a hash code value for the object.

Calculates a hash code value for the object.

The default hashing algorithm is platform dependent.

Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

Attributes

Returns

the hash code value for this object.

Definition Classes
Any
Source
Ordering.scala

Inherited methods

override def equiv(x: Option[T], y: Option[T]): Boolean

Return true if x == y in the ordering.

Return true if x == y in the ordering.

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
override def gt(x: Option[T], y: Option[T]): Boolean

Return true if x > y in the ordering.

Return true if x > y in the ordering.

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
override def gteq(x: Option[T], y: Option[T]): Boolean

Return true if x >= y in the ordering.

Return true if x >= y in the ordering.

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
def isReverseOf(other: Ordering[_]): Boolean

Returns whether or not the other ordering is the opposite ordering of this one.

Returns whether or not the other ordering is the opposite ordering of this one.

Equivalent to other == this.reverse.

Implementations should only override this method if they are overriding reverse as well.

Attributes

Inherited from:
Ordering
Source
Ordering.scala
override def lt(x: Option[T], y: Option[T]): Boolean

Return true if x < y in the ordering.

Return true if x < y in the ordering.

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
override def lteq(x: Option[T], y: Option[T]): Boolean

Return true if x <= y in the ordering.

Return true if x <= y in the ordering.

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
def max[U <: Option[T]](x: U, y: U): U

Return x if x >= y, otherwise y.

Return x if x >= y, otherwise y.

Attributes

Inherited from:
Ordering
Source
Ordering.scala
def min[U <: Option[T]](x: U, y: U): U

Return x if x <= y, otherwise y.

Return x if x <= y, otherwise y.

Attributes

Inherited from:
Ordering
Source
Ordering.scala
def on[U](f: U => Option[T]): Ordering[U]

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

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

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

Attributes

Inherited from:
Ordering
Source
Ordering.scala
def orElse(other: Ordering[Option[T]]): Ordering[Option[T]]

Creates an Ordering[T] whose compare function returns the result of this Ordering's compare function, if it is non-zero, or else the result of others compare function.

Creates an Ordering[T] whose compare function returns the result of this Ordering's compare function, if it is non-zero, or else the result of others compare function.

Value parameters

other

an Ordering to use if this Ordering returns zero

Attributes

Example 

case class Pair(a: Int, b: Int)
val pairOrdering = Ordering.by[Pair, Int](_.a)
                          .orElse(Ordering.by[Pair, Int](_.b))
Inherited from:
Ordering
Source
Ordering.scala
def orElseBy[S](f: Option[T] => S)(implicit ord: Ordering[S]): Ordering[Option[T]]

Given f, a function from T into S, creates an Ordering[T] whose compare function returns the result of this Ordering's compare function, if it is non-zero, or else a result equivalent to:

Given f, a function from T into S, creates an Ordering[T] whose compare function returns the result of this Ordering's compare function, if it is non-zero, or else a result equivalent to:

Ordering[S].compare(f(x), f(y))

This function is equivalent to passing the result of Ordering.by(f) to orElse.

Attributes

Example 

case class Pair(a: Int, b: Int)
val pairOrdering = Ordering.by[Pair, Int](_.a)
                          .orElseBy[Int](_.b)
Inherited from:
Ordering
Source
Ordering.scala
override def reverse: Ordering[Option[T]]

Return the opposite ordering of this one.

Return the opposite ordering of this one.

Implementations overriding this method MUST override isReverseOf as well if they change the behavior at all (for example, caching does not require overriding it).

Attributes

Definition Classes
Inherited from:
Ordering
Source
Ordering.scala
def reversed(): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparing[U <: Comparable[_ >: U <: <FromJavaObject>]](x$0: Function[_ >: Option[T] <: <FromJavaObject>, _ <: U]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparing[U <: <FromJavaObject>](x$0: Function[_ >: Option[T] <: <FromJavaObject>, _ <: U], x$1: Comparator[_ >: U <: <FromJavaObject>]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparing(x$0: Comparator[_ >: Option[T] <: <FromJavaObject>]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparingDouble(x$0: ToDoubleFunction[_ >: Option[T] <: <FromJavaObject>]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparingInt(x$0: ToIntFunction[_ >: Option[T] <: <FromJavaObject>]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def thenComparingLong(x$0: ToLongFunction[_ >: Option[T] <: <FromJavaObject>]): Comparator[Option[T]]

Attributes

Inherited from:
Comparator
def tryCompare(x: Option[T], y: Option[T]): Some[Int]

Returns whether a comparison between x and y is defined, and if so the result of compare(x, y).

Returns whether a comparison between x and y is defined, and if so the result of compare(x, y).

Attributes

Inherited from:
Ordering
Source
Ordering.scala

Implicits

Inherited implicits

implicit def mkOrderingOps(lhs: Option[T]): OrderingOps

This implicit method augments T with the comparison operators defined in scala.math.Ordering.Ops.

This implicit method augments T with the comparison operators defined in scala.math.Ordering.Ops.

Attributes

Inherited from:
Ordering
Source
Ordering.scala
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Copyright (c) 2002-2024, LAMP/EPFL
Copyright (c) 2002-2024, LAMP/EPFL