Dart Iterable

Summary: in this tutorial, you’ll learn about the Dart Iterable<E> class and its methods for managing elements of a collection effectively.

Introduction to the Dart Iterable<E> class

An iterable is a collection of elements that can be accessed sequentially. Dart uses the Iterable<E> abstract class to represent iterable objects.

An iterable object has an iterator getter that returns an iterator object. The iterable object uses the iterator to step through its elements.

Each time you access the iterator getter, the iterable object returns a new iterator. For this reason, you can create more than one iterator from the same iterable object.

If an object is iterable, you can use the for-in statement to iterate over its elements.

Since List and Set are iterable, you can use the for-in statement to iterate over their elements. For example:

void main() {
  Iterable<int> iterable = [1, 2, 3, 4, 5];
  for (var n in iterable) {
    print(n);
  }
}Code language: Dart (dart)

In this example, we assign a list to an iterable and use the for-in loop to display the elements.

The first and last properties return the first and last elements respectively. For example:

void main() {
  Iterable<int> iterable = [1, 2, 3, 4, 5];
  print(iterable.first);
  print(iterable.last);
}Code language: Dart (dart)

Unlike a list, you cannot access an element via an iterable object using the square brackets []. Instead, you use the elementAt() method:

void main() {
  Iterable<int> iterable = [1, 2, 3, 4, 5];
  print(iterable.elementAt(1));
}Code language: Dart (dart)

Output:

2Code language: plaintext (plaintext)

Summary

• An iterable is a collection of elements that can be accessed sequentially.
• Dart uses the Iterable<E> abstract class to represent iterable objects.