Working with iterables in Dart

What is an iterable?

An iterable is a collection of elements that can be accessed sequentially. It is a generalization of a list. It is a way to access a collection of objects. It is an object that can be iterated upon. It is an object that implements the Iterable interface.

What is an iterator?

An iterator is an object that provides access to the elements of an iterable collection. It helps you to loop through the elements of a collection. It is also called a cursor.

Working with iterables

Now, lets create a simple iterable and loop through it to print its elements.

 
void main () { 
 
// Create an iterable using the Iterable constructor of length 10 
 
var iterable = Iterable<int>.generate(10);
 
// Loop through the iterable using the for-in loop
 
for (var element in iterable) {
 
print(element);
 
} 
 
 
}
 

Output

0
1
2
3
4
5
6
7
8
9

Accessing the elements of an iterable

You can access the elements of an iterable using the the following methods:

• elementAt() method
• first property
• last property
• single property
• firstWhere() method
• lastWhere() method
• singleWhere() method

And so on ..

Example

Now, lets access the elements of an iterable.

 
void main () {
 
// Create an iterable using the Iterable constructor of length 10
 
var iterable = Iterable<int>.generate(10);
 
// Access the elements of the iterable using the elementAt() method
 
print(iterable.elementAt(0));
 
print(iterable.elementAt(1));
 
print(iterable.elementAt(2));
 
print(iterable.elementAt(3));
 

Output

0
1
2
3

Iterating over an iterable

You can iterate over an iterable using the following methods:

• forEach() method
• map() method
• where() method
• whereType() method
• expand() method

And so on ..

Example

Now, lets iterate over an iterable.

 
void main () {
 
// Create an iterable using the Iterable constructor of length 10
 
var iterable = Iterable<int>.generate(10);
 
// Iterate over the iterable using the forEach() method
 
iterable.forEach((element) => print(element));
 

Output

0
1
2
3
4
5
6
7
8
9

You can use loops like this to iterate over an iterable.

Conclusion

So, in this tutorial, we learned:

• What is an iterable?
• How to create an iterable?
• How to access the elements of an iterable?
• How to iterate over an iterable?