 # Sets in Dart

Published on 29 March 2020
Last Updated on 29 March 2020

## What are Sets in Dart

A set is a unique collection of items added in an unordered list.

### Program that demonstrates how to use Sets in Dart

``````void main(List<String> args) {
// a set of alphabet
var alphabet = {'a', 'b', 'c', 'd'};
print('alphabet is \${alphabet}');

// an empty set of numbers
var numberSet = <int>{};
print('numberSet is \${numberSet}');

// a set of even numbers
var evenNumberSet = <int>{2, 4};
print('evenNumberSet is \${evenNumberSet}');

// adding items to an empty set

// adding even numbers to set of numbers

print('evenNumberSet is \${evenNumberSet}');

// using .length to read how many items are there in the set
print('numberSet has \${numberSet.length} items in it.');

// sets that are compile time constant
const fruits = {
'apple',
'orange',
'banana',
'watermelon',
};
print('fruits set is \${fruits}');
}
``````

Running above program will produce following output:

``````alphabet is {a, b, c, d}
numberSet is {}
evenNumberSet is {2, 4}
evenNumberSet is {2, 4}
numberSet has 3 items in it.
fruits set is {apple, orange, banana, watermelon}
``````

### Defining an empty set in dart

As shown in program given below, an empty set can be defined by using following syntax:

``````// an empty set of numbers
var numberSet = <int>{};
``````

### Adding new item or a set of items to an existing set

Use following syntax to add new elements to an existing set of items.

``````numberSet.add(0);
``````const fruits = {