What is an Iterator?

An iterator in Python is an object that implements two methods: __iter__() and __next__(). The __iter__() method returns the iterator object itself and is called once at the beginning of an iteration. The __next__() method returns the next value from the sequence and raises a StopIteration exception when there are no more items to return.

Define the Iterator Class:

• __init__: The constructor initializes the maximum value (max_n) and the current value (current), which starts at 0.
• __iter__: This method returns the iterator object itself. It is called once at the beginning of the iteration.
• __next__: This method calculates the square of the current value, increments the current value, and returns the result. If the current value exceeds max_n, it raises a StopIteration exception to signal the end of the iteration.

Why Use Custom Iterators?

Custom iterators allow you to:

• Encapsulate complex iteration logic.
• Maintain state between iterations.
• Generate values on the fly (lazy evaluation), which can be more memory-efficient for large datasets.

Iterators are a fundamental concept in Python, allowing you to traverse through all the elements in a collection, such as lists or tuples. While Python provides built-in iterators, there are times when you might need to create your own custom iterator to handle more complex data structures or operations. In this article, we will explore how to build a basic iterator in Python from scratch.