Generators

Generators are very powerful tools. They are based on the concept of iteration, as we said before, and they allow for coding patterns that combine elegance with efficiency.

Generators are of two types:

• Generator functions: These are very similar to regular functions, but instead of returning results through return statements, they use yield, which allows them to suspend and resume their state between each call.
• Generator expressions: These are very similar to the list comprehensions we've seen in this chapter, but instead of returning a list, they return an object that produces results one by one.

Generator functions

Generator functions behave like regular functions in all respects, except for one difference: instead of collecting results and returning them at once, they are automatically turned into iterators that yield results one at a time when you call next on them. Generator functions are automatically turned into their own...