#    
## Overview
We can use the **`isNotEmpty` property** of `HashSet` to confirm that a `HashSet` is not empty. 

> Note: **`HashSet`** is an unordered, `Hashtable`-based set. You can read more about `HashSet`[here](https://api.dart.dev/stable/2.14.4/dart-collection/HashSet-class.html).

## Syntax 

```dart
bool isNotEmpty
```

## Return value 

This property returns `True` if the set contains at least one element. Otherwise, it returns `False`.

## Code

The code below demonstrates how to check if a `HashSet` is not empty.

import 'dart:collection';
void main() {
  // create a new HashSet
  HashSet set = new HashSet();

  print("set is : $set");
  // check it the set is not empty
  print("Is set Not Empty : ${set.isNotEmpty}");

  // add elements to the set
  set.add(10);
  set.add(20);
  print("set is : $set");
  // check it the set is not empty
  print("Is set Not Empty : ${set.isNotEmpty}");
}


#     
## Code explanation

 - Line 1: We import the collection library.

 - Line 4: We create a `HashSet` with the name `set`.

-  Line 8: We use the `isNotEmpty` property to check if `set` is empty or not. In this case, `set` does not contain any elements, so the property returns `False`.

-  Lines 11–12: We use the `add()` method to add two elements, `10` and `20`, to the set.

- Line 15: We use the `isNotEmpty` property to check if `set` is empty or not. Now, `set` contains two elements, so the property returns `True`.

How to check if a HashSet is not empty in Dart

Use the isNotEmpty property of a HashSet in Dart to check if it contains elements.