Alg

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)

Given Eq[A], return a PartialOrder[A] using the combine operator to determine the partial ordering. This method assumes combine functions as join (that is, as an upper bound).

This method returns:

0.0 if x = y -1.0 if y = combine(x, y) 1.0 if x = combine(x, y) NaN otherwise

Given Eq[A], return a PartialOrder[A] using the combine operator to determine the partial ordering. This method assumes combine functions as meet (that is, as a lower bound).

This method returns:

0.0 if x = y -1.0 if x = combine(x, y) 1.0 if y = combine(x, y) NaN otherwise

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

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