Trait/Object

cats.kernel

Semigroup

Related Docs: object Semigroup | package kernel

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trait Semigroup[A] extends Serializable

A semigroup is any set A with an associative operation (combine).

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Abstract Value Members

  1. abstract def combine(x: A, y: A): A

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    Associative operation which combines two values.

    Associative operation which combines two values.

    Example:

    scala> import cats.kernel.instances.string._
    scala> import cats.kernel.instances.int._
    scala> import cats.kernel.instances.option._
    
    scala> Semigroup[String].combine("Hello ", "World!")
    res0: String = Hello World!
    
    scala> Semigroup[Option[Int]].combine(None, Some(1))
    res1: Option[Int] = Some(1)
  2. abstract def getClass(): Class[_]

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Concrete Value Members

  1. final def !=(arg0: Any): Boolean

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  2. final def ##(): Int

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  3. final def ==(arg0: Any): Boolean

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  4. final def asInstanceOf[T0]: T0

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  5. def combineAllOption(as: TraversableOnce[A]): Option[A]

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    Given a sequence of as, combine them and return the total.

    Given a sequence of as, combine them and return the total.

    If the sequence is empty, returns None. Otherwise, returns Some(total).

    Example:

    scala> import cats.kernel.instances.string._
    
    scala> Semigroup[String].combineAllOption(List("One ", "Two ", "Three"))
    res0: Option[String] = Some(One Two Three)
    
    scala> Semigroup[String].combineAllOption(List.empty)
    res1: Option[String] = None
  6. def combineN(a: A, n: Int): A

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    Return a combined with itself n times.

    Return a combined with itself n times.

    Example:

    scala> import cats.kernel.instances.int._
    scala> import cats.kernel.instances.string._
    
    scala> Semigroup[Int].combineN(1, 10)
    res0: Int = 10
    
    scala> Semigroup[String].combineN("ha", 3)
    res1: String = hahaha
  7. def equals(arg0: Any): Boolean

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  8. def hashCode(): Int

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  9. final def isInstanceOf[T0]: Boolean

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  10. def repeatedCombineN(a: A, n: Int): A

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    Return a combined with itself more than once.

    Return a combined with itself more than once.

    Attributes
    protected[this]
  11. def toString(): String

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Inherited from Serializable

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