The essence of the for loop is the application of the iterator protocol, which retrieves elements one by one using iter() and next(), until the stopIteration exception is raised.1. iter is a built-in function in Python that converts an object into an iterator.
2. next() retrieves elements one by one, and raises an exception if there are no more elements.
3. So why does the for loop not raise an error during execution? Because the exception is caught.
4. Let’s popularize the concepts of iterable objects and iterators.Iterable objects (Iterable): Objects that implement the __iter__() method and can be traversed using for, including lists, strings, dictionaries, etc. Iterators (Iterator): Objects that implement both __iter__() and __next__() methods, serving as “value retrieval tools.” All iterators are iterable, but not all iterable objects are iterators.This concludes today’s sharing. Please leave a comment for corrections or discussions if there are any errors.