scala.math

# Ordered

#### trait Ordered[A] extends Comparable[A]

A trait for data that have a single, natural ordering. See scala.math.Ordering before using this trait for more information about whether to use scala.math.Ordering instead.

Classes that implement this trait can be sorted with scala.util.Sorting and can be compared with standard comparison operators (e.g. > and <).

Ordered should be used for data with a single, natural ordering (like integers) while Ordering allows for multiple ordering implementations. An Ordering instance will be implicitly created if necessary.

scala.math.Ordering is an alternative to this trait that allows multiple orderings to be defined for the same type.

scala.math.PartiallyOrdered is an alternative to this trait for partially ordered data.

For example, create a simple class that implements `Ordered` and then sort it with scala.util.Sorting:

    case class OrderedClass(n:Int) extends Ordered[OrderedClass] {
    	def compare(that: OrderedClass) =  this.n - that.n
    }

    val x = Array(OrderedClass(1), OrderedClass(5), OrderedClass(3))
    scala.util.Sorting.quickSort(x)
    x

It is important that the `equals` method for an instance of `Ordered[A]` be consistent with the compare method. However, due to limitations inherent in the type erasure semantics, there is no reasonable way to provide a default implementation of equality for instances of `Ordered[A]`. Therefore, if you need to be able to use equality on an instance of `Ordered[A]` you must provide it yourself either when inheriting or instantiating.

It is important that the `hashCode` method for an instance of `Ordered[A]` be consistent with the `compare` method. However, it is not possible to provide a sensible default implementation. Therefore, if you need to be able compute the hash of an instance of `Ordered[A]` you must provide it yourself either when inheriting or instantiating.

Source
  Ordered.scala
Version

  1.1, 2006-07-24

See also

  scala.math.Ordering, scala.math.PartiallyOrdered

Linear Supertypes
Comparable[A], Any
Known Subclasses
Deadline, Duration, FiniteDuration, FractionalProxy, Infinite, IntegralProxy, OrderedProxy, RichBoolean, RichByte, RichChar, RichDouble, RichFloat, RichInt, RichLong, RichShort, ScalaNumberProxy, ScalaWholeNumberProxy, StringBuilder, StringLike, StringOps, Val, Value, Value, WrappedString
Type Hierarchy Learn more about scaladoc diagrams
Ordering

1. Alphabetic
2. By inheritance

Inherited

1. Ordered
2. Comparable
3. Any

Implicitly

1. by orderingToOrdered
2. by any2stringadd
3. by any2stringfmt
4. by any2ArrowAssoc
5. by any2Ensuring

1. Hide All
2. Show all

Learn more about member selection
Visibility

1. Public
2. All

### Abstract Value Members

1. #### abstract def compare(that: A): Int

   Result of comparing `this` with operand `that`.

   Result of comparing `this` with operand `that`.

   Implement this method to determine how instances of A will be sorted.

   Returns `x` where:

   - `x < 0` when `this < that`
   - `x == 0` when `this == that`
   - `x > 0` when `this > that`

2. #### abstract 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
     Any

### Concrete 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
     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
     Any

3. #### def +(other: String): String

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to StringAdd performed by method any2stringadd in scala.Predef.
   Definition Classes
     StringAdd

4. #### def ->[B](y: B): (Ordered[A], B)

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to ArrowAssoc[Ordered[A]] performed by method any2ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### def <(that: A): Boolean

   Returns true if `this` is less than `that`

6. #### def <=(that: A): Boolean

   Returns true if `this` is less than or equal to `that`.

7. #### final def ==(arg0: Any): Boolean

   Test two objects for equality.

   Test two objects for equality. 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
     Any

8. #### def >(that: A): Boolean

   Returns true if `this` is greater than `that`.

9. #### def >=(that: A): Boolean

   Returns true if `this` is greater than or equal to `that`.

10. #### 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`.

11. #### def compareTo(that: A): Int

    Result of comparing `this` with operand `that`.

    Result of comparing `this` with operand `that`.

    Definition Classes
      Ordered → Comparable

12. #### def ensuring(cond: (Ordered[A]) ⇒ Boolean, msg: ⇒ Any): Ordered[A]

    Implicit information
      This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method any2Ensuring in scala.Predef.
    Definition Classes
      Ensuring

13. #### def ensuring(cond: (Ordered[A]) ⇒ Boolean): Ordered[A]

    Implicit information
      This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method any2Ensuring in scala.Predef.
    Definition Classes
      Ensuring

14. #### def ensuring(cond: Boolean, msg: ⇒ Any): Ordered[A]

    Implicit information
      This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method any2Ensuring in scala.Predef.
    Definition Classes
      Ensuring

15. #### def ensuring(cond: Boolean): Ordered[A]

    Implicit information
      This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method any2Ensuring in scala.Predef.
    Definition Classes
      Ensuring

16. #### def equals(arg0: 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 `AnyRef` 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)`).

    returns

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

    Definition Classes
      Any

17. #### 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 information
      This member is added by an implicit conversion from Ordered[A] to StringFormat performed by method any2stringfmt in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

18. #### def hashCode(): Int

    Calculate a hash code value for the object.

    Calculate 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.

    returns

      the hash code value for this object.

    Definition Classes
      Any

19. #### 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

20. #### def toString(): String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

      a string representation of the object.

    Definition Classes
      Any

21. #### def →[B](y: B): (Ordered[A], B)

    Implicit information
      This member is added by an implicit conversion from Ordered[A] to ArrowAssoc[Ordered[A]] performed by method any2ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### Shadowed Implicit Value Members

1. #### def <(that: Ordered[A]): Boolean

   Returns true if `this` is less than `that`

   Returns true if `this` is less than `that`

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).<(that)

2. #### def <=(that: Ordered[A]): Boolean

   Returns true if `this` is less than or equal to `that`.

   Returns true if `this` is less than or equal to `that`.

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).<=(that)

3. #### def >(that: Ordered[A]): Boolean

   Returns true if `this` is greater than `that`.

   Returns true if `this` is greater than `that`.

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).>(that)

4. #### def >=(that: Ordered[A]): Boolean

   Returns true if `this` is greater than or equal to `that`.

   Returns true if `this` is greater than or equal to `that`.

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).>=(that)

5. #### def compare(that: Ordered[A]): Int

   Result of comparing `this` with operand `that`.

   Result of comparing `this` with operand `that`.

   Implement this method to determine how instances of A will be sorted.

   Returns `x` where:

   - `x < 0` when `this < that`
   - `x == 0` when `this == that`
   - `x > 0` when `this > that`
   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).compare(that)

6. #### def compareTo(that: Ordered[A]): Int

   Result of comparing `this` with operand `that`.

   Result of comparing `this` with operand `that`.

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ordered[Ordered[A]] performed by method orderingToOrdered in scala.math.Ordered. This conversion will take place only if an implicit value of type Ordering[Ordered[A]] is in scope.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (ordered: Ordered[Ordered[A]]).compareTo(that)

   Definition Classes
     Ordered → Comparable

7. #### val self: Any

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to StringAdd performed by method any2stringadd in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (ordered: StringAdd).self

   Definition Classes
     StringAdd

8. #### val self: Any

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to StringFormat performed by method any2stringfmt in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (ordered: StringFormat).self

   Definition Classes
     StringFormat

### Deprecated Value Members

1. #### def x: Ordered[A]

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to ArrowAssoc[Ordered[A]] performed by method any2ArrowAssoc in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (ordered: ArrowAssoc[Ordered[A]]).x

   Definition Classes
     ArrowAssoc
   Annotations
     @deprecated
   Deprecated

     (Since version 2.10.0) Use `leftOfArrow`instead``

2. #### def x: Ordered[A]

   Implicit information
     This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method any2Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (ordered: Ensuring[Ordered[A]]).x

   Definition Classes
     Ensuring
   Annotations
     @deprecated
   Deprecated

     (Since version 2.10.0) Use `resultOfEnsuring`instead``

### Inherited from Comparable[A]

### Inherited from Any

### Inherited by implicit conversion orderingToOrdered from Ordered[A] to Ordered[Ordered[A]]

### Inherited by implicit conversion any2stringadd from Ordered[A] to StringAdd

### Inherited by implicit conversion any2stringfmt from Ordered[A] to StringFormat

### Inherited by implicit conversion any2ArrowAssoc from Ordered[A] to ArrowAssoc[Ordered[A]]

### Inherited by implicit conversion any2Ensuring from Ordered[A] to Ensuring[Ordered[A]]

### Ungrouped