Chapter 9. The Iterator Pattern
We've discussed how many of Python's built-ins and idioms that seem, at first blush, to be non-object-oriented are actually providing access to major objects under the hood. In this chapter, we'll discuss how the for loop that seems so structured is actually a lightweight wrapper around a set of object-oriented principles. We'll also see a variety of extensions to this syntax that automatically create even more types of object. We will cover:
What design patterns are
The iterator protocol—one of the most powerful design patterns
List, set, and dictionary comprehensions
Generators and coroutines
