FunctorFilter

abstract def functor: Functor[F]

abstract def mapFilter[A, B](fa: F[A])(f: (A) ⇒ Option[B]): F[B]

A combined map and filter.

scala> import cats.implicits._
scala> val m: Map[Int, String] = Map(1 -> "one", 3 -> "three")
scala> val l: List[Int] = List(1, 2, 3, 4)
scala> def asString(i: Int): Option[String] = m.get(i)
scala> l.mapFilter(i => m.get(i))
res0: List[String] = List(one, three)

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

def collect[A, B](fa: F[A])(f: PartialFunction[A, B]): F[B]

Similar to mapFilter but uses a partial function instead of a function that returns an Option.

scala> import cats.implicits._
scala> val l: List[Int] = List(1, 2, 3, 4)
scala> FunctorFilter[List].collect(l){
     |   case 1 => "one"
     |   case 3 => "three"
     | }
res0: List[String] = List(one, three)

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def filter[A](fa: F[A])(f: (A) ⇒ Boolean): F[A]

Apply a filter to a structure such that the output structure contains all A elements in the input structure that satisfy the predicate f but none that don't.

def finalize(): Unit

def flattenOption[A](fa: F[Option[A]]): F[A]

"Flatten" out a structure by collapsing Options.

scala> import cats.implicits._
scala> val l: List[Option[Int]] = List(Some(1), None, Some(3), None)
scala> l.flattenOption
res0: List[Int] = List(1, 3)

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit