How to use the union() method of LinkedHashSet in Dart

Overview

The union() method returns a new set by combining all the elements of the current set with the Set passed as an argument.

Syntax

Set<E> union(Set<E> other)

Parameter

This method takes a Set to be combined with the current Set as an argument.

Return value

This method returns a new set with all the elements of the current Set and the Set that is passed as an argument.

Code

The code below demonstrates the use of the union() method :

import 'dart:collection';
void main() {
  //create a new LinkedHashSet which can have int type elements
  LinkedHashSet set1 = new LinkedHashSet<int>();
  // add three elements to the set
  set1.add(1);
  set1.add(2);
  set1.add(3);
  print('The set1 is $set1');
  //create another LinkedHashSet 
  LinkedHashSet set2 = new LinkedHashSet<int>();
  // add three elements to the set
  set2.add(3);
  set2.add(4);
  set2.add(5);
  print('The set2 is $set2');
  var unionResult = set1.union(set2); // combine set1 and set2
  print('\nset1.union(set2) : $unionResult');
}

Explanation

  • Line 1: We import the collection library.

  • Lines 4 to 9: We create a new LinkedHashSet object named set1. We then use the add() method to add three elements (1,2,3) to the set1 object.

  • Lines 13 to 17: We create another LinkedHashSet object named set2. We then use the add() method to add three elements (3,4,5) to the set2 object.

  • Line 20: We use the union() method on set1 with set2 as an argument. This method returns a new Set containing all the set1 and set2 elements. The elements of the returned set are [1,2,3,4,5].

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