Iterators vs. Iterables in Python : In Python, iterators and iterables are fundamental concepts in dealing with collections of data. An iterable is any object that can be looped over, such as lists, strings, or dictionaries. An iterator, on the other hand, is an object that is responsible for iterating over an iterable, providing access to its elements one at a time. Understanding the difference between these concepts is crucial for efficient and flexible data handling in Python.

Iter() function in Python : The iter() function in Python is a built-in function that is used to create an iterator from an iterable object. It enables developers to access the elements of an iterable sequentially by returning an iterator object. By calling the next() function on the iterator, elements can be retrieved one at a time, allowing for efficient and controlled iteration over the iterable.

Custom sequence type in Python : In Python, it is possible to create custom sequence types by defining classes that implement special methods and protocols. By following the guidelines set by the sequence protocol, developers can create objects that behave like sequences, supporting operations such as indexing, slicing, and iterating. Custom sequence types provide flexibility and control over the behavior of objects, allowing for customized data structures and workflows in Python.