Trait scala.math.Ordered
Companion object Ordered
trait Ordered[A] extends Comparable[A]
Abstract Value Members
abstract def compare(that: A): Int
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
abstract def getClass(): Class[_]
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
final def !=(arg0: Any): Boolean
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- Any
final def ##(): Int
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
def +(other: String): String
- Implicit
- This member is added by an implicit conversion from Ordered[A] to any2stringadd[Ordered[A]] performed by method any2stringadd in scala.Predef.
- Definition Classes
- any2stringadd
def ->[B](y: B): (Ordered[A], B)
- Implicit
- This member is added by an implicit conversion from Ordered[A] to ArrowAssoc[Ordered[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
def <(that: A): Boolean
def <=(that: A): Boolean
final def ==(arg0: Any): Boolean
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
def >(that: A): Boolean
def >=(that: A): Boolean
final def asInstanceOf[T0]: 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 typeT0
.
def compareTo(that: A): Int
Result of comparing this
with operand that
.
- Definition Classes
- Ordered → Comparable
def ensuring(cond: (Ordered[A]) ⇒ Boolean, msg: ⇒ Any): Ordered[A]
- Implicit
- This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: (Ordered[A]) ⇒ Boolean): Ordered[A]
- Implicit
- This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): Ordered[A]
- Implicit
- This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def ensuring(cond: Boolean): Ordered[A]
- Implicit
- This member is added by an implicit conversion from Ordered[A] to Ensuring[Ordered[A]] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
def equals(arg0: Any): Boolean
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)
).
- returns
true
if the receiver object is equivalent to the argument;false
otherwise.
- Definition Classes
- Any
def formatted(fmtstr: String): String
Returns string formatted according to given format
string. Format strings are as for String.format
(@see java.lang.String.format).
- Implicit
- This member is added by an implicit conversion from Ordered[A] to StringFormat[Ordered[A]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @inline()
def hashCode(): Int
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
final def isInstanceOf[T0]: Boolean
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 typeT0
;false
otherwise.
- Definition Classes
- Any
def toString(): String
Returns a string representation of the object.
The default representation is platform dependent.
- returns
a string representation of the object.
- Definition Classes
- Any
def →[B](y: B): (Ordered[A], B)
- Implicit
- This member is added by an implicit conversion from Ordered[A] to ArrowAssoc[Ordered[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/math/Ordered.html
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:It is important that the
equals
method for an instance ofOrdered[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 ofOrdered[A]
. Therefore, if you need to be able to use equality on an instance ofOrdered[A]
you must provide it yourself either when inheriting or instantiating.It is important that the
hashCode
method for an instance ofOrdered[A]
be consistent with thecompare
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 ofOrdered[A]
you must provide it yourself either when inheriting or instantiating.scala.math.Ordering, scala.math.PartiallyOrdered