what is Functional Collections in Scala

Category : Scala | Sub Category : Scala Interview Questions | By Prasad Bonam Last updated: 2023-09-27 00:14:28 Viewed : 273

Functional collections in Scala are collections that emphasize and encourage functional programming principles. They provide a set of operations and transformations that allow you to work with collections in a functional and immutable way. Scalas standard library includes a rich set of functional collections that promote immutability, concise code, and expressive data transformations. Here are some key functional collections in Scala:

1. List:

   Scalas List is a functional collection that represents an ordered, immutable, and linked list. You can perform operations like map, filter, reduce, and others in a functional style.

   scalaCopy code
   val myList = List(1, 2, 3, 4, 5)
   val doubledList = myList.map(_ * 2)
   

2. Seq (Sequence):

   Seq is a trait that represents a sequence of elements. It includes both List and Vector, among others, as concrete implementations. Seq provides a functional API for working with sequences.

   scalaCopy code
   val mySeq = Seq(1, 2, 3, 4, 5)
   val squaredSeq = mySeq.map(x => x * x)
   

3. Set:

   Scalas Set is an immutable collection that represents an unordered set of distinct elements. You can perform set operations like union, intersection, and difference in a functional way.

   scalaCopy code
   val set1 = Set(1, 2, 3)
   val set2 = Set(2, 3, 4)
   val unionSet = set1.union(set2)
   

4. Map:

   Map is a functional collection representing a collection of key-value pairs. You can use functional operations to transform and manipulate maps.

   scalaCopy code
   val myMap = Map("Alice" -> 25, "Bob" -> 30, "Carol" -> 28)
   val ageAfterBirthday = myMap.map { case (name, age) => (name, age + 1) }
   

5. Option:

   While not a traditional collection, Option is a functional type in Scala used to represent optional values. It can contain either Some value or None. It encourages safe handling of potential absence of values.

   scalaCopy code
   val maybeValue: Option[Int] = Some(42)
   val doubledValue = maybeValue.map(_ * 2)
   

Functional collections in Scala promote immutability and provide methods that return new collections instead of modifying the existing ones. This allows for safer and more predictable code in concurrent and parallel scenarios. Functional programming with collections is a powerful paradigm in Scala that helps developers write concise and expressive code while maintaining code correctness and safety.