The `dart:collection` library provides advanced collection support for the Dart language. The library contains the **`HashSet<E>`** class, which is an unordered hash-table-based implementation of the abstract `Set<E>` class.

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## The **`any()`** method
The `HashSet<E>` class contains the **`any()`** method, which is used to check if any of the elements of the HashSet satisfy the specified input condition.
>**`HashSet<E>`** is a collection of unique elements that provides constant-time `add`, `remove`, and `contains` operations. `HashSet<E>` does not have a specified iteration order. However, multiple iterations on the set produce the same element order.

The figure below illustrates how the `any()` method works.

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## Syntax
The syntax of the `any()` method is as follows:
```
bool any(bool test(E element))
```
## Parameters
The `any()` method takes a predicate `test` as input and checks every element of the HashSet against the predicate.

## Return value
`any()` returns `true` if any  HashSet elements satisfy the input predicate; otherwise, it returns `false`.

## Code
The code below shows how the `any()` method works in Dart.


import 'dart:collection'; 
void main() { 
   var countrySet = HashSet<String>();
   
   countrySet.add("America"); 
   countrySet.add("Japan"); 
   countrySet.add("India");
   countrySet.add("UAE");
   
   print('Printing Set Elements');
   print(countrySet); 

  var result = countrySet.any((e)=>e.length==3);
  print('Does set contains a country name of length = 3 : $result');
   
}  

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## Explanation
* Line 3: We create an instance of a `HashSet` class of type `String`.

* Lines 5-8: Next, we use the `add()` method to add a few country names to the HashSet: `"America"`, `"Japan"`, `"India"`, and `"UAE"`.

* Line 13: We call the `any()` method with a predicate that `returns` true if the string's length is equal to three. The method returns `true` because the HashSet contains `"UAE"`, which is of length 3.

* Line 14: We use the `print()` function of the core library to display the set elements and the result of the `any()` method.

What is HashSet.any() in Dart?

Checks if any HashSet elements satisfy a condition, returning true if met, else false.

What is HashSet.any() in Dart?

The any() method

Syntax

Parameters

Return value

Code

Explanation

The `any()` method