trait FunctorFilter[F[_]] extends Serializable
FunctorFilter[F] allows you to map and filter out elements simultaneously.
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- FunctorFilter.scala
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- abstract def functor: Functor[F]
- abstract def mapFilter[A, B](fa: F[A])(f: (A) => Option[B]): F[B]
A combined
mapandfilter.A combined
mapandfilter. Filtering is handled viaOptioninstead ofBooleansuch that the output typeBcan be different than the input typeA.Example:
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(asString) res0: List[String] = List(one, three)
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- final def !=(arg0: Any): Boolean
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- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- 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.Similar to mapFilter but uses a partial function instead of a function that returns an
Option.Example:
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
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- def equals(arg0: AnyRef): Boolean
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- def filter[A](fa: F[A])(f: (A) => Boolean): F[A]
Apply a filter to a structure such that the output structure contains all
Aelements in the input structure that satisfy the predicatefbut none that don't. - def filterNot[A](fa: F[A])(f: (A) => Boolean): F[A]
Apply a filter to a structure such that the output structure contains all
Aelements in the input structure that do not satisfy the predicatef. - def finalize(): Unit
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- @throws(classOf[java.lang.Throwable])
- def flattenOption[A](fa: F[Option[A]]): F[A]
"Flatten" out a structure by collapsing
Options."Flatten" out a structure by collapsing
Options. Equivalent to usingmapFilterwithidentity.Example:
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)
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