Set in Dart
Set In Dart
Set is a unique collection of items. You cannot store duplicate values in the Set. It is unordered, so it can be faster than lists while working with a large amount of data. Set is useful when you need to store unique values without considering the order of the input. E.g., fruits name, months name, days name, etc. It is represented by Curley Braces{}.
Note: The list allows you to add duplicate items, but the Set doesn’t allow it.
Syntax
Set <variable_type> variable_name = {};
How To Create A Set In Dart
You can create a Set in Dart using the Set type annotation. Here Set<String> means only text is allowed in the Set.
void main(){
Set<String> fruits = {"Apple", "Orange", "Mango"};
print(fruits);
}
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Set Properties In Dart
| Properties | Work |
|---|---|
| first | To get first value of Set. |
| last | To get last value of Set. |
| isEmpty | Return true or false. |
| isNotEmpty | Return true or false. |
| length | It returns the length of the Set. |
Example of Set Properties Dart
This example finds the first and last element of the Set, checks whether it is empty or not, and finds its length.
void main() {
// declaring fruits as Set
Set<String> fruits = {"Apple", "Orange", "Mango", "Banana"};
// using different properties of Set
print("First Value is ${fruits.first}");
print("Last Value is ${fruits.last}");
print("Is fruits empty? ${fruits.isEmpty}");
print("Is fruits not empty? ${fruits.isNotEmpty}");
print("The length of fruits is ${fruits.length}");
}
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Check The Available Value
If you want to see whether the Set contains specific items or not, you can use the contains method, which returns true or false.
void main(){
Set<String> fruits = {"Apple", "Orange", "Mango"};
print(fruits.contains("Mango"));
print(fruits.contains("Lemon"));
}
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Add & Remove Items In Set
Like lists, you can add or remove items in a Set. To add items use add() method and to remove use remove() method.
| Method | Description |
|---|---|
| add() | Add one element to Set. |
| remove() | Removes one element from Set. |
void main(){
Set<String> fruits = {"Apple", "Orange", "Mango"};
fruits.add("Lemon");
fruits.add("Grape");
print("After Adding Lemon and Grape: $fruits");
fruits.remove("Apple");
print("After Removing Apple: $fruits");
}
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Adding Multiple Elements
You can use addAll() method to add multiple elements from the list to Set.
| Method | Description |
|---|---|
| addAll() | Insert the multiple values to the given Set. |
void main(){
Set<int> numbers = {10, 20, 30};
numbers.addAll([40,50]);
print("After adding 40 and 50: $numbers");
}
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Printing All Values In Set
You can print all Set items by using loops. Click here if you want to learn loop in dart.
void main(){
Set<String> fruits = {"Apple", "Orange", "Mango"};
for(String fruit in fruits){
print(fruit);
}
}
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Set Methods In Dart
Some other helpful Set methods in dart.
| Method | Description |
|---|---|
| clear() | Removes all elements from the Set. |
| difference() | Creates a new Set with the elements of this that are not in other. |
| elementAt() | Returns the index value of element. |
| intersection() | Find common elements in two sets. |
Clear Set In Dart
In this example, you can see how to remove all items from the Set in dart.
void main() {
Set<String> fruits = {"Apple", "Orange", "Mango"};
// to clear all items
fruits.clear();
print(fruits);
}
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Difference In Set
In Dart, the difference method creates a new Set with the elements that are not in the other.
void main() {
Set<String> fruits1 = {"Apple", "Orange", "Mango"};
Set<String> fruits2 = {"Apple", "Grapes", "Banana"};
final differenceSet = fruits1.difference(fruits2);
print(differenceSet);
}
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Element At Method In Dart
In Dart you can find the Set value by its index number. The index number starts with 0.
void main() {
Set<String> days = {"Sunday", "Monday", "Tuesday"};
// index starts from 0 so 2 means Tuesday
print(days.elementAt(2));
}
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Intersection Method In Dart
In Dart, the intersection method creates a new Set with the common elements in 2 Sets. Here Apple is available in both Sets.
void main() {
Set<String> fruits1 = {"Apple", "Orange", "Mango"};
Set<String> fruits2 = {"Apple", "Grapes", "Banana"};
final intersectionSet = fruits1.intersection(fruits2);
print(intersectionSet);
}
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Video
Watch our video on the set in Dart.