implicit object Unit extends UnitOrdering
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- Ordering.scala
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- Unit
- UnitOrdering
- Ordering
- PartialOrdering
- Equiv
- Serializable
- Comparator
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Type Members
- class OrderingOps extends AnyRef
This inner class defines comparison operators available for
T.This inner class defines comparison operators available for
T.It can't extend
AnyValbecause it is not a top-level class or a member of a statically accessible object.- Definition Classes
- Ordering
Value Members
- final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
trueif !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
- final def ##: Int
Equivalent to
x.hashCodeexcept for boxed numeric types andnull.Equivalent to
x.hashCodeexcept 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. Fornullreturns a hashcode wherenull.hashCodethrows aNullPointerException.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).- returns
trueif the receiver object is equivalent to the argument;falseotherwise.
- Definition Classes
- AnyRef → Any
- 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 aClassCastExceptionat 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
ClassCastExceptionif the receiver object is not an instance of the erasure of typeT0.
- def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clonemethod is platform dependent.- returns
a copy of the receiver object.
- def compare(x: Unit, y: Unit): 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)
- Definition Classes
- UnitOrdering → Ordering → Comparator
- 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
eqmethod implements an equivalence relation on non-null instances ofAnyRef, and has three additional properties:- It is consistent: for any non-null instances
xandyof typeAnyRef, multiple invocations ofx.eq(y)consistently returnstrueor consistently returnsfalse. - For any non-null instance
xof typeAnyRef,x.eq(null)andnull.eq(x)returnsfalse. null.eq(null)returnstrue.
When overriding the
equalsorhashCodemethods, 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
trueif the argument is a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- def equiv(x: Unit, y: Unit): Boolean
Return true if
x==yin the ordering.Return true if
x==yin the ordering.- Definition Classes
- Ordering → PartialOrdering → Equiv
- 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
finalizemethod is invoked, as well as the interaction betweenfinalizeand non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- Note
not specified by SLS as a member of AnyRef
- final def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
- def gt(x: Unit, y: Unit): Boolean
Return true if
x>yin the ordering.Return true if
x>yin the ordering.- Definition Classes
- Ordering → PartialOrdering
- def gteq(x: Unit, y: Unit): Boolean
Return true if
x>=yin the ordering.Return true if
x>=yin the ordering.- Definition Classes
- Ordering → PartialOrdering
- def hashCode(): Int
The hashCode method for reference types.
- final def isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object has the same erasure as
T0.Test whether the dynamic type of the receiver object has the same erasure as
T0.Depending on what
T0is, the test is done in one of the below ways:T0is a non-parameterized class type, e.g.BigDecimal: this method returnstrueif the value of the receiver object is aBigDecimalor a subtype ofBigDecimal.T0is a parameterized class type, e.g.List[Int]: this method returnstrueif the value of the receiver object is someList[X]for anyX. For example,List(1, 2, 3).isInstanceOf[List[String]]will return true.T0is some singleton typex.typeor literalx: this method returnsthis.eq(x). For example,x.isInstanceOf[1]is equivalent tox.eq(1)T0is an intersectionX with YorX & Y: this method is equivalent tox.isInstanceOf[X] && x.isInstanceOf[Y]T0is a unionX | Y: this method is equivalent tox.isInstanceOf[X] || x.isInstanceOf[Y]T0is a type parameter or an abstract type member: this method is equivalent toisInstanceOf[U]whereUisT0's upper bound,AnyifT0is unbounded. For example,x.isInstanceOf[A]whereAis an unbounded type parameter will return true for any value ofx.
This is exactly equivalent to the type pattern
_: T0- returns
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
- Note
due to the unexpectedness of
List(1, 2, 3).isInstanceOf[List[String]]returning true andx.isInstanceOf[A]whereAis a type parameter or abstract member returning true, these forms issue a warning.
- def isReverseOf(other: Ordering[_]): Boolean
Returns whether or not the other ordering is the opposite ordering of this one.
- def lt(x: Unit, y: Unit): Boolean
Return true if
x<yin the ordering.Return true if
x<yin the ordering.- Definition Classes
- Ordering → PartialOrdering
- def lteq(x: Unit, y: Unit): Boolean
Return true if
x<=yin the ordering.Return true if
x<=yin the ordering.- Definition Classes
- Ordering → PartialOrdering
- def max[U <: Unit](x: U, y: U): U
Return
xifx>=y, otherwisey.Return
xifx>=y, otherwisey.- Definition Classes
- Ordering
- def min[U <: Unit](x: U, y: U): U
Return
xifx<=y, otherwisey.Return
xifx<=y, otherwisey.- Definition Classes
- Ordering
- implicit def mkOrderingOps(lhs: Unit): OrderingOps
This implicit method augments
Twith the comparison operators defined inscala.math.Ordering.Ops.This implicit method augments
Twith the comparison operators defined inscala.math.Ordering.Ops.- Definition Classes
- Ordering
- final def ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that).Equivalent to
!(this eq that).- returns
trueif the argument is not a reference to the receiver object;falseotherwise.
- 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
- def on[U](f: (U) => Unit): 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))- Definition Classes
- Ordering
- def orElse(other: Ordering[Unit]): Ordering[Unit]
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.- other
an Ordering to use if this Ordering returns zero
- Definition Classes
- Ordering
case class Pair(a: Int, b: Int) val pairOrdering = Ordering.by[Pair, Int](_.a) .orElse(Ordering.by[Pair, Int](_.b))
Example: - def orElseBy[S](f: (Unit) => S)(implicit ord: Ordering[S]): Ordering[Unit]
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)toorElse.- Definition Classes
- Ordering
case class Pair(a: Int, b: Int) val pairOrdering = Ordering.by[Pair, Int](_.a) .orElseBy[Int](_.b)
Example: - def reverse: Ordering[Unit]
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).
- Definition Classes
- Ordering → PartialOrdering
- def reversed(): Comparator[Unit]
- Definition Classes
- Comparator
- final def synchronized[T0](arg0: => T0): T0
Executes the code in
bodywith an exclusive lock onthis.Executes the code in
bodywith an exclusive lock onthis.- returns
the result of
body
- Definition Classes
- AnyRef
- def thenComparing[U <: Comparable[_ >: U <: AnyRef]](arg0: java.util.function.Function[_ >: Unit <: AnyRef, _ <: U]): Comparator[Unit]
- Definition Classes
- Comparator
- def thenComparing[U <: AnyRef](arg0: java.util.function.Function[_ >: Unit <: AnyRef, _ <: U], arg1: Comparator[_ >: U <: AnyRef]): Comparator[Unit]
- Definition Classes
- Comparator
- def thenComparing(arg0: Comparator[_ >: Unit <: AnyRef]): Comparator[Unit]
- Definition Classes
- Comparator
- def thenComparingDouble(arg0: ToDoubleFunction[_ >: Unit <: AnyRef]): Comparator[Unit]
- Definition Classes
- Comparator
- def thenComparingInt(arg0: ToIntFunction[_ >: Unit <: AnyRef]): Comparator[Unit]
- Definition Classes
- Comparator
- def thenComparingLong(arg0: ToLongFunction[_ >: Unit <: AnyRef]): Comparator[Unit]
- Definition Classes
- Comparator
- 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
- def tryCompare(x: Unit, y: Unit): Some[Int]
Returns whether a comparison between
xandyis defined, and if so the result ofcompare(x, y).Returns whether a comparison between
xandyis defined, and if so the result ofcompare(x, y).- Definition Classes
- Ordering → PartialOrdering
- final def wait(): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long, arg1: Int): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int,Float,ArrayorOptionwhich are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collectionand its sub-packages contain Scala's collections frameworkscala.collection.immutable- Immutable, sequential data-structures such asVector,List,Range,HashMaporHashSetscala.collection.mutable- Mutable, sequential data-structures such asArrayBuffer,StringBuilder,HashMaporHashSetscala.collection.concurrent- Mutable, concurrent data-structures such asTrieMapscala.concurrent- Primitives for concurrent programming such asFuturesandPromisesscala.io- Input and output operationsscala.math- Basic math functions and additional numeric types likeBigIntandBigDecimalscala.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.Predefobject are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
Listis an alias forscala.collection.immutable.List.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
Stringis an alias forjava.lang.String.