How to get the last element of the SplayTreeSet in Dart

Overview

We can use the last property to get the last element present in a SplayTreeSet.

If the set is empty, a StateError is thrown.

Syntax

E last

Return value

This method returns the last element present in the set.

Code

The code below demonstrates how to get the last element of the SplayTreeSet:

import 'dart:collection';
void main() {
  //create a new SplayTreeSet which can have int type elements
  SplayTreeSet set = new SplayTreeSet<int>((a,b) =>  b.compareTo(a));
  // add three elements to the set
  set.add(5);
  set.add(4);
  set.add(3);
  print('The set is $set');
  print('The last element of set is ${set.last}');
  // delete all elements of the set
  set.clear();
  try { 
    // if set contains no elements, accessing last will result in error
    print(set.last); 
  } catch(e) { 
      print(e);
  } 
}

Explanation

In the code above,

  • Line 1: We import the collection library.

  • Line 4: We create a new SplayTreeSet object with the name set. We then pass a compare function as an argument. This function will be used to maintain the order of the set elements. In our case, our compare function will order elements in descending order.

  • Lines 7-9: We add three new elements to the set. Now the set is {5,4,3}.

  • Line 12: We get the last element of the set using the last property.

  • Line 15: We remove all elements of the set using the clear method.

  • Line 18: We try to access the last property of the empty set. This throws a StateError saying that no element is present in the set.

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