In the last article, we saw how generator functions using yield provide a memory-efficient way to create iterators. Python offers an even more concise and elegant way to create simple generators: generator expressions.
In the last article, we learned how to create a custom iterator by building a class that implements the full iterator protocol (iter and next). While this is powerful, it's also quite verbose for many common use cases.
One of the most powerful and frequently used features in Python is the for loop. We use it to loop over lists, strings, dictionaries, and files. But how does it actually work? How does the for loop know how to handle all these different types of objects?