object Ordering extends LowPriorityOrderingImplicits with java.io.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
- Alphabetic
- By Inheritance
- Ordering
- Serializable
- LowPriorityOrderingImplicits
- AnyRef
- Any
- Hide All
- Show All
- Public
- All
Type Members
- type AsComparable[A] = (A) => Comparable[_ >: A]
- Definition Classes
- LowPriorityOrderingImplicits
- trait BigDecimalOrdering extends Ordering[BigDecimal]
- trait BigIntOrdering extends Ordering[BigInt]
- trait BooleanOrdering extends Ordering[Boolean]
- trait ByteOrdering extends Ordering[Byte]
- sealed trait CachedReverse[T] extends Ordering[T]
An ordering which caches the value of its reverse.
- trait CharOrdering extends Ordering[Char]
- trait ExtraImplicits extends AnyRef
- trait IntOrdering extends Ordering[Int]
- trait LongOrdering extends Ordering[Long]
- trait OptionOrdering[T] extends Ordering[Option[T]]
- trait ShortOrdering extends Ordering[Short]
- trait StringOrdering extends Ordering[String]
- trait SymbolOrdering extends Ordering[Symbol]
- trait UnitOrdering extends Ordering[Unit]
Value Members
- 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
- final def ##(): Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. 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. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (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
- AnyRef → Any
- implicit def Option[T](implicit ord: Ordering[T]): Ordering[Option[T]]
- implicit def Tuple2[T1, T2](implicit ord1: Ordering[T1], ord2: Ordering[T2]): Ordering[(T1, T2)]
- implicit def Tuple3[T1, T2, T3](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3]): Ordering[(T1, T2, T3)]
- implicit def Tuple4[T1, T2, T3, T4](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4]): Ordering[(T1, T2, T3, T4)]
- implicit def Tuple5[T1, T2, T3, T4, T5](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4], ord5: Ordering[T5]): Ordering[(T1, T2, T3, T4, T5)]
- implicit def Tuple6[T1, T2, T3, T4, T5, T6](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4], ord5: Ordering[T5], ord6: Ordering[T6]): Ordering[(T1, T2, T3, T4, T5, T6)]
- implicit def Tuple7[T1, T2, T3, T4, T5, T6, T7](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4], ord5: Ordering[T5], ord6: Ordering[T6], ord7: Ordering[T7]): Ordering[(T1, T2, T3, T4, T5, T6, T7)]
- implicit def Tuple8[T1, T2, T3, T4, T5, T6, T7, T8](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4], ord5: Ordering[T5], ord6: Ordering[T6], ord7: Ordering[T7], ord8: Ordering[T8]): Ordering[(T1, T2, T3, T4, T5, T6, T7, T8)]
- implicit def Tuple9[T1, T2, T3, T4, T5, T6, T7, T8, T9](implicit ord1: Ordering[T1], ord2: Ordering[T2], ord3: Ordering[T3], ord4: Ordering[T4], ord5: Ordering[T5], ord6: Ordering[T6], ord7: Ordering[T7], ord8: Ordering[T8], ord9: Ordering[T9]): Ordering[(T1, T2, T3, T4, T5, T6, T7, T8, T9)]
- def apply[T](implicit ord: Ordering[T]): Ordering[T]
- Annotations
- @inline()
- 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 aClassCastException
at runtime, while the expressionList(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 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.
- 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.
- implicit def comparatorToOrdering[A](implicit cmp: Comparator[A]): Ordering[A]
- Definition Classes
- LowPriorityOrderingImplicits
- final def eq(arg0: AnyRef): Boolean
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
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
- It is consistent: for any non-null instances
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- 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 betweenfinalize
and non-local returns and exceptions, are all platform dependent. - def fromLessThan[T](cmp: (T, T) => Boolean): Ordering[T]
Construct an Ordering[T] given a function
lt
. - final def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
- def hashCode(): Int
The hashCode method for reference types.
- 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 returnfalse
, while the expressionList(1).isInstanceOf[List[String]]
will returntrue
. 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
- 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
- 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
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- 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
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- implicit def ordered[A](implicit asComparable: AsComparable[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. SinceOrdered[A]
extendsComparable[A]
anyway, we can throw in some Java interop too.- Definition Classes
- LowPriorityOrderingImplicits
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- 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
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- implicit object BigDecimal extends BigDecimalOrdering
- implicit object BigInt extends BigIntOrdering
- implicit object Boolean extends BooleanOrdering
- implicit object Byte extends ByteOrdering
- implicit object Char extends CharOrdering
- object Double
Ordering
s forDouble
s. - object Float
Ordering
s forFloat
s. - object Implicits extends ExtraImplicits
An object containing implicits which are not in the default scope.
- implicit object Int extends IntOrdering with CachedReverse[Int]
- implicit object Long extends LongOrdering
- implicit object Short extends ShortOrdering
- implicit object String extends StringOrdering
- implicit object Symbol extends SymbolOrdering
- implicit object Unit extends UnitOrdering
Deprecated Value Members
- implicit def Iterable[T](implicit ord: Ordering[T]): Ordering[Iterable[T]]
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0)
- implicit object DeprecatedDoubleOrdering extends TotalOrdering
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0)
- implicit object DeprecatedFloatOrdering extends TotalOrdering
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0)
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.collection.parallel
- Parallel collections (scala-parallel-collections.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.