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Scala 3
3.7.4
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Copyright (c) 2002-2025, LAMP/EPFL
Copyright (c) 2002-2025, LAMP/EPFL
Scala 3/scala/scala.util/Right

Right

scala.util.Right
final caseclassRight[+A,+B](value:B) extendsEither[A,B]

The right side of the disjoint union, as opposed to thescala.util.Left side.

Attributes

Source
Either.scala
Graph
Supertypes
classEither[A,B]
traitProduct
traitEquals
classObject
traitMatchable
classAny
Show all

Members list

Value members

Concrete methods

Returnstrue if this is aLeft,false otherwise.

Returnstrue if this is aLeft,false otherwise.

Left("tulip").isLeft // trueRight("venus fly-trap").isLeft // false

Attributes

Source
Either.scala

Returnstrue if this is aRight,false otherwise.

Returnstrue if this is aRight,false otherwise.

Left("tulip").isRight // falseRight("venus fly-trap").isRight // true

Attributes

Source
Either.scala
defwithLeft[A1 >:A]:Either[A1,B]

Upcasts thisRight[A, B] toEither[A1, B]

Upcasts thisRight[A, B] toEither[A1, B]

Right("x")               // Either[Nothing, String]Right("x").withLeft[Int] // Either[Int, String]

Attributes

Source
Either.scala

Inherited methods

finaldefcontains[B1 >:B](elem:B1):Boolean

Returnstrue if this is aRight and its value is equal toelem (as determined by==), returnsfalse otherwise.

Returnstrue if this is aRight and its value is equal toelem (as determined by==), returnsfalse otherwise.

// Returns true because value of Right is "something" which equals "something".Right("something") contains "something"// Returns false because value of Right is "something" which does not equal "anything".Right("something") contains "anything"// Returns false because it's not a Right value.Left("something") contains "something"

Value parameters

elem

the element to test.

Attributes

Returns

true if this is aRight value equal toelem.

Inherited from:
Either
Source
Either.scala

Returnsfalse ifLeft or returns the result of the application of the given predicate to theRight value.

Returnsfalse ifLeft or returns the result of the application of the given predicate to theRight value.

Right(12).exists(_ > 10)   // trueRight(7).exists(_ > 10)    // falseLeft(12).exists(_ => true) // false

Attributes

Inherited from:
Either
Source
Either.scala
deffilterOrElse[A1 >:A](p:B=>Boolean,zero:=>A1):Either[A1,B]

ReturnsRight with the existing value ofRight if this is aRight and the given predicatep holds for the right value, orLeft(zero) if this is aRight and the given predicatep does not hold for the right value, orLeft with the existing value ofLeft if this is aLeft.

ReturnsRight with the existing value ofRight if this is aRight and the given predicatep holds for the right value, orLeft(zero) if this is aRight and the given predicatep does not hold for the right value, orLeft with the existing value ofLeft if this is aLeft.

Right(12).filterOrElse(_ > 10, -1)   // Right(12)Right(7).filterOrElse(_ > 10, -1)    // Left(-1)Left(7).filterOrElse(_ => false, -1) // Left(7)

Attributes

Inherited from:
Either
Source
Either.scala
defflatMap[A1 >:A,B1](f:B=>Either[A1,B1]):Either[A1,B1]

Binds the given function acrossRight.

Binds the given function acrossRight.

Value parameters

f

The function to bind acrossRight.

Attributes

Inherited from:
Either
Source
Either.scala
defflatten[A1 >:A,B1](implicitev:B<:<Either[A1,B1]):Either[A1,B1]

Returns the right value if this is right or this value if this is left

Returns the right value if this is right or this value if this is left

Attributes

Example

val  l: Either[String, Either[String, Int]] = Left("pancake")val rl: Either[String, Either[String, Int]] = Right(Left("flounder"))val rr: Either[String, Either[String, Int]] = Right(Right(7))l.flatten //Either[String, Int]: Left("pancake")rl.flatten //Either[String, Int]: Left("flounder")rr.flatten //Either[String, Int]: Right(7)

Equivalent toflatMap(id => id)

Inherited from:
Either
Source
Either.scala
deffold[C](fa:A=>C,fb:B=>C):C

Appliesfa if this is aLeft orfb if this is aRight.

Appliesfa if this is aLeft orfb if this is aRight.

Value parameters

fa

the function to apply if this is aLeft

fb

the function to apply if this is aRight

Attributes

Returns

the results of applying the function

Example

val result = util.Try("42".toInt).toEitherresult.fold(  e => s"Operation failed with $e",  v => s"Operation produced value: $v")
Inherited from:
Either
Source
Either.scala

Returnstrue ifLeft or returns the result of the application of the given predicate to theRight value.

Returnstrue ifLeft or returns the result of the application of the given predicate to theRight value.

Right(12).forall(_ > 10)    // trueRight(7).forall(_ > 10)     // falseLeft(12).forall(_ => false) // true

Attributes

Inherited from:
Either
Source
Either.scala
defforeach[U](f:B=>U):Unit

Executes the given side-effecting function if this is aRight.

Executes the given side-effecting function if this is aRight.

Right(12).foreach(println) // prints "12"Left(12).foreach(println)  // doesn't print

Value parameters

f

The side-effecting function to execute.

Attributes

Inherited from:
Either
Source
Either.scala
defgetOrElse[B1 >:B](or:=>B1):B1

Returns the value from thisRight or the given argument if this is aLeft.

Returns the value from thisRight or the given argument if this is aLeft.

Right(12).getOrElse(17) // 12Left(12).getOrElse(17)  // 17

Attributes

Inherited from:
Either
Source
Either.scala
defjoinLeft[A1 >:A,B1 >:B,C](implicitev:A1<:<Either[C,B1]):Either[C,B1]

Joins anEither throughLeft.

Joins anEither throughLeft.

This method requires that the left side of thisEither is itself anEither type. That is, this must be some type like:

Either[Either[C, B], B]

(which respects the type parameter bounds, shown below.)

If this instance is aLeft[Either[C, B]] then the containedEither[C, B] will be returned, otherwise this value will be returned unmodified.

Left[Either[Int, String], String](Right("flower")).joinLeft // Result: Right("flower")Left[Either[Int, String], String](Left(12)).joinLeft // Result: Left(12)Right[Either[Int, String], String]("daisy").joinLeft // Result: Right("daisy")

This method, andjoinRight, are analogous toOption#flatten.

Attributes

Inherited from:
Either
Source
Either.scala
defjoinRight[A1 >:A,B1 >:B,C](implicitev:B1<:<Either[A1,C]):Either[A1,C]

Joins anEither throughRight.

Joins anEither throughRight.

This method requires that the right side of thisEither is itself anEither type. That is, this must be some type like:

Either[A, Either[A, C]]

(which respects the type parameter bounds, shown below.)

If this instance is aRight[Either[A, C]] then the containedEither[A, C] will be returned, otherwise this value will be returned unmodified.

Attributes

Example

Right[String, Either[String, Int]](Right(12)).joinRight // Result: Right(12)Right[String, Either[String, Int]](Left("flower")).joinRight // Result: Left("flower")Left[String, Either[String, Int]]("flower").joinRight // Result: Left("flower")

This method, andjoinLeft, are analogous toOption#flatten

Inherited from:
Either
Source
Either.scala

Projects thisEither as aLeft.

Projects thisEither as aLeft.

This allows for-comprehensions over the left side ofEither instances, reversingEither's usual right-bias.

For example

for (s <- Left("flower").left) yield s.length // Left(6)

Continuing the analogy withscala.Option, aLeftProjection declares thatLeft should be analogous toSome in some code.

// using Optiondef interactWithDB(x: Query): Option[Result] =  try Some(getResultFromDatabase(x))  catch {    case _: SQLException => None  }// this will only be executed if interactWithDB returns a Someval report = for (result <- interactWithDB(someQuery)) yield generateReport(result)report match {  case Some(r) => send(r)  case None    => log("report not generated, not sure why...")}// using Eitherdef interactWithDB(x: Query): Either[Exception, Result] =  try Right(getResultFromDatabase(x))  catch {    case e: SQLException => Left(e)  } // run a report only if interactWithDB returns a Right val report = for (result <- interactWithDB(someQuery)) yield generateReport(result) report match {   case Right(r) => send(r)   case Left(e)  => log(s"report not generated, reason was $e") } // only report errors for (e <- interactWithDB(someQuery).left) log(s"query failed, reason was $e")

Attributes

Inherited from:
Either
Source
Either.scala
defmap[B1](f:B=>B1):Either[A,B1]

The given function is applied if this is aRight.

The given function is applied if this is aRight.

Right(12).map(x => "flower") // Result: Right("flower")Left(12).map(x => "flower")  // Result: Left(12)

Attributes

Inherited from:
Either
Source
Either.scala
deforElse[A1 >:A,B1 >:B](or:=>Either[A1,B1]):Either[A1,B1]

Returns thisRight or the given argument if this is aLeft.

Returns thisRight or the given argument if this is aLeft.

Right(1) orElse Left(2) // Right(1)Left(1) orElse Left(2)  // Left(2)Left(1) orElse Left(2) orElse Right(3) // Right(3)

Attributes

Inherited from:
Either
Source
Either.scala

An iterator over the names of all the elements of this product.

An iterator over the names of all the elements of this product.

Attributes

Inherited from:
Product
Source
Product.scala

An iterator over all the elements of this product.

An iterator over all the elements of this product.

Attributes

Returns

in the default implementation, anIterator[Any]

Inherited from:
Product
Source
Product.scala
defswap:Either[B,A]

If this is aLeft, then return the left value inRight or vice versa.

If this is aLeft, then return the left value inRight or vice versa.

Attributes

Example

val left: Either[String, Int]  = Left("left")val right: Either[Int, String] = left.swap // Result: Right("left")

val right = Right(2)val left  = Left(3)for {  r1 <- right  r2 <- left.swap} yield r1 * r2 // Right(6)
Inherited from:
Either
Source
Either.scala

Returns aSome containing theRight value if it exists or aNone if this is aLeft.

Returns aSome containing theRight value if it exists or aNone if this is aLeft.

Right(12).toOption // Some(12)Left(12).toOption  // None

Attributes

Inherited from:
Either
Source
Either.scala
deftoSeq:Seq[B]

Returns aSeq containing theRight value if it exists or an emptySeq if this is aLeft.

Returns aSeq containing theRight value if it exists or an emptySeq if this is aLeft.

Right(12).toSeq // Seq(12)Left(12).toSeq  // Seq()

Attributes

Inherited from:
Either
Source
Either.scala
deftoTry(implicitev:A<:<Throwable):Try[B]

Attributes

Inherited from:
Either
Source
Either.scala

Deprecated and Inherited methods

Projects thisEither as aRight.

Projects thisEither as aRight.

BecauseEither is right-biased, this method is not normally needed.

Attributes

Deprecated
[Since version 2.13.0]Either is now right-biased, use methods directly on Either
Inherited from:
Either
Source
Either.scala
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Copyright (c) 2002-2025, LAMP/EPFL
Copyright (c) 2002-2025, LAMP/EPFL

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