monoid
Value members
Concrete methods
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)
Inherited methods
Given a sequence of as
, sum them using the monoid and return the total.
Given a sequence of as
, sum them using the monoid and return the total.
Example:
scala> import cats.kernel.instances.string._
scala> Monoid[String].combineAll(List("One ", "Two ", "Three"))
res0: String = One Two Three
scala> Monoid[String].combineAll(List.empty)
res1: String = ""
- Inherited from:
- Monoid
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
- Definition Classes
- Monoid -> Semigroup
- Inherited from:
- Monoid
Return a
appended to itself n
times.
Return a
appended to itself n
times.
Example:
scala> import cats.kernel.instances.string._
scala> Monoid[String].combineN("ha", 3)
res0: String = hahaha
scala> Monoid[String].combineN("ha", 0)
res1: String = ""
- Definition Classes
- Monoid -> Semigroup
- Inherited from:
- Monoid
Between each pair of elements insert middle This name matches the term used in Foldable and Reducible and a similar Haskell function.
Between each pair of elements insert middle This name matches the term used in Foldable and Reducible and a similar Haskell function.
- Inherited from:
- Semigroup
Tests if a
is the identity.
Tests if a
is the identity.
Example:
scala> import cats.kernel.instances.string._
scala> Monoid[String].isEmpty("")
res0: Boolean = true
scala> Monoid[String].isEmpty("something")
res1: Boolean = false
- Inherited from:
- Monoid