StringMonoid

cats.kernel.instances.StringMonoid
class StringMonoid extends Monoid[String]

Attributes

Source
StringInstances.scala
Graph
Supertypes
trait Monoid[String]
trait Semigroup[String]
trait Serializable
class Object
trait Matchable
class Any
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Self type

Members list

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)

Attributes

Source
StringInstances.scala

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 = ""

Attributes

Definition Classes
Source
StringInstances.scala
def empty: String

Return the identity element for this monoid.

Return the identity element for this monoid.

Example:

scala> import cats.kernel.instances.int._
scala> import cats.kernel.instances.string._

scala> Monoid[String].empty
res0: String = ""

scala> Monoid[Int].empty
res1: Int = 0

Attributes

Source
StringInstances.scala
override def reverse: Monoid[String]

return a semigroup that reverses the order so combine(a, b) == reverse.combine(b, a)

return a semigroup that reverses the order so combine(a, b) == reverse.combine(b, a)

Attributes

Definition Classes
Source
StringInstances.scala

Inherited methods

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

Attributes

Definition Classes
Inherited from:
Monoid
Source
Monoid.scala
override def combineN(a: String, n: Int): String

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 = ""

Attributes

Definition Classes
Inherited from:
Monoid
Source
Monoid.scala

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.

Attributes

Inherited from:
Semigroup
Source
Semigroup.scala
def isEmpty(a: String)(implicit ev: Eq[String]): Boolean

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

Attributes

Inherited from:
Monoid
Source
Monoid.scala