Python 3 - Second Edition

21    Generators and Iterators

In the previous chapters, we frequently used terms such as iterate or iterable object. Without having defined this exactly, it’s intuitively clear that this means the successive consideration of the individual elements of a corresponding instance. For example, a for loop can be used to iterate over a list:

>>> for x in [1,2,3,4]:...     print(x)... 1234  

In this chapter, we want to put the notion of iterating on a solid footing by introducing the central concepts of generators and iterators. Then you’ll get to know itertools, a module of the standard library that provides a collection of generators for various interesting use cases.

21.1    Generators

In this section, we’ll describe the concept of generators, which can ...