Set in Scala

 

Set

Scala Set is a collection of pairwise different elements of the same type. In other words, a Set is a collection that contains no duplicate elements. There are two kinds of Sets, the immutable and themutable. The difference between mutable and immutable objects is that when an object is immutable, the object itself can't be changed.

By default, Scala uses the immutable Set. If you want to use the mutable Set, you'll have to import scala.collection.mutable.Set class explicitly. If you want to use both mutable and immutable sets in the same, then you can continue to refer to the immutable Set as Set but you can refer to the mutable Set as mutable.Set

// Empty set of integer type

 var s : Set[Int] = Set()

// Set of integer type

var s : Set[Int] = Set(1,3,5,7)

or

var s = Set(1,3,5,7)

Basic Operations on Set:

Head àThis method returns the first element of a set.

Tail àThis method returns a set consisting of all elements except the first.

isEmpty à This method returns true if the set is empty otherwise false.

val fruit = Set("apples", "oranges", "pears")

val nums: Set[Int] = Set()

println( "Head of fruit : " + fruit.head )

println( "Tail of fruit : " + fruit.tail )

println( "Check if fruit is empty : " + fruit.isEmpty )

println( "Check if nums is empty : " + nums.isEmpty )

Output :

Head of fruit : apples

Tail of fruit : Set(oranges, pears)

Check if fruit is empty : false

Check if nums is empty : true

//

val num = Set(5,6,9,20,30,45)

println(num.max)  //45

println(num.min) //5

var myset2 = Set(10, 100, 1000, 10000, 100000) 

println("\nSet 2:") 

myset2.foreach((item:Int)=>println(item))

Output :

Set 2: 10 100000 10000 1000 100

var myset = Set("G", "Geek", "for") // Creating and initilazing set

myset += "Geeks" // using += and ++==

myset ++== List("Geeks12", "geek23", "G")

Get sorted values from Set

import scala.collection.immutable.SortedSet

val myset: SortedSet[Int] = SortedSet(87, 0, 3, 45, 7, 56, 8,6) 

myset.foreach((items: Int)=> println(items)) 
var myset = Set(100, 400, 500, 600, 300, 800) 

// Deleting elements in set

// using -= and --= methods

myset -= 600

myset --= List(300, 100)

Output:

Set before deletion:

Set(300, 100, 800, 500, 600, 400)

Set after deletion:

Set(800, 500, 400)

// using clear() method

myset2. clear

var myset1 = Set(100, 400, 500,600,300, 800)

// using retain() method

myset1.retain(_>500)

Output :

Set(800, 600)

// Creating and initializing set

val myset1 = Set(11, 22, 33, 44,55, 66, 77, 111)

val myset2 = Set(88, 22, 99, 44,55, 66, 77)

val S1 = myset1.intersect(myset2)

println(S1)

Output:

Set(77, 22, 44, 66, 55)

// To find the symmetric difference

val S2 = myset1.diff(myset2)

println(S2)

Output:

Set(33, 11, 111)

// To find union

val S3 = myset1.union(myset2)

println(S3)

Output:

Set(88, 33, 77, 22, 44, 66, 11, 99, 55, 111)

Note : Set display value in random order.