The Python Apprentice

Generators

• Generator functions allow us to describe sequences using imperative code.

• Generator functions contain at least one use of the yield keyword.

• Generators are iterators. When the iterator is advanced with next() the generator starts or resumes execution up to and including the next yield.

• Each call to a generator function creates a new generator object.

• Generators can maintain explicit state in local variables between iterations.

• Generators are lazy and so can model infinite series of data.

• Generator expressions have a similar syntactic form to list comprehensions and allow for a more declarative and concise way of creating generator objects.