[Python-ideas] Re: Enhancing iterator objects with map, filter, reduce methods

On Sun, Nov 28, 2021, 8:59 PM Steven D'Aprano

To be an iterator, your object needs:

1. a `__next__` method which returns the next value; 2. and an `__iter__` method which returns self.

That's not quite right. An iterator only needs .__next__(), and an iterable only needs .__iter__(). Returning self is a convenient, and probably the most common, way of creating an object that is both. But exceptions exist, and remain iterators and/or iterables.