Iterators in Python

In the previous lesson, we pondered over the decency of the for loop. Now let’s unveil it and see the magic behind it.

What is an iterator?

In Python, an iterator is an object that implements the __iter__ and __next__ dunder methods.

⚙️ Note: Dunder methods are methods having two prefix and suffix underscores in the method name. They are also known as magic methods. For example: __init__, __len__, __repr__, etc.

The __iter__() function returns an iterator object that goes through each element of the given object. Whereas, the __next__() function returns the next item in the sequence.

Objects that support the __iter__ and __next__ methods automatically work with loops.

Iterator from scratch

To create an iterator class, it must implement the __iter__() and __next() methods. Let’s create an iterator that returns numbers.