Ordering

Related Docs: trait Ordering | package math

object Ordering extends LowPriorityOrderingImplicits with Serializable

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.

Source
Ordering.scala
Linear Supertypes
Ordering
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Inherited
1. Ordering
2. Serializable
3. Serializable
4. LowPriorityOrderingImplicits
5. AnyRef
6. Any
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Visibility
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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. 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)`.

arg0

the object to compare against this object for equality.

returns

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

Definition Classes
AnyRef → Any

11. object Implicits extends ExtraImplicits

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

28. 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

Definition Classes
Any
Exceptions thrown

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

29. def by[T, S](f: (T) ⇒ S)(implicit ord: Ordering[S]): Ordering[T]

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

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.

30. 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[java.lang]
Definition Classes
AnyRef
Annotations
( ... )
Note

not specified by SLS as a member of AnyRef

31. implicit def comparatorToOrdering[A](implicit cmp: Comparator[A]): Ordering[A]

Definition Classes
LowPriorityOrderingImplicits
32. 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
33. 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
34. 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[java.lang]
Definition Classes
AnyRef
Annotations
( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

35. def fromLessThan[T](cmp: (T, T) ⇒ Boolean): Ordering[T]

Construct an Ordering[T] given a function `lt`.

36. 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

37. 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
38. 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
39. 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
40. 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

41. 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

42. implicit def ordered[A](implicit arg0: (A) ⇒ Comparable[A]): Ordering[A]

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.

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.

Definition Classes
LowPriorityOrderingImplicits
43. final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
44. 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
45. final def wait(): Unit

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

Definition Classes
AnyRef
Annotations
( ... )
47. final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
( ... )