Learning Python - Mark Lutz [12]
Many additions and changes were made with Python beginners in mind, and some topics were moved to appear at the places where they proved simplest to digest in training classes. List comprehensions and iterators, for example, now make their initial appearance in conjunction with the for loop statement, instead of later with functional tools.
Coverage of many original core language topics also was substantially expanded in the third edition, with new discussions and examples added. Because this text has become something of a de facto standard resource for learning the core Python language, the presentation was made more complete and augmented with new use cases throughout.
In addition, a new set of Python tips and tricks, gleaned from 10 years of teaching classes and 15 years of using Python for real work, was incorporated, and the exercises were updated and expanded to reflect current Python best practices, new language features, and common beginners’ mistakes witnessed firsthand in classes. Overall, the core language coverage was expanded.
The Third Edition’s Structural Changes
Because the material was more complete, it was split into bite-sized chunks. The core language material was organized into many multichapter parts to make it easier to tackle. Types and statements, for instance, are now two top-level parts, with one chapter for each major type and statement topic. Exercises and “gotchas” (common mistakes) were also moved from chapter ends to part ends, appearing at the end of the last chapter in each part.
In the third edition, I also augmented the end-of-part exercises with end-of-chapter summaries and end-of-chapter quizzes to help you review chapters as you complete them. Each chapter concludes with a set of questions to help you review and test your understanding of the chapter’s material. Unlike the end-of-part exercises, whose solutions are presented in Appendix B, the solutions to the end-of-chapter quizzes appear immediately after the questions; I encourage you to look at the solutions even if you’re sure you’ve answered the questions correctly because the answers are a sort of review in themselves.
Despite all the new topics, the book is still oriented toward Python newcomers and is designed to be a first Python text for programmers. Because it is largely based on time-tested training experience and materials, it can still serve as a self-paced introductory Python class.
The Third Edition’s Scope Changes
As of its third edition, this book is intended as a tutorial on the core Python language, and nothing else. It’s about learning the language in an in-depth fashion, before applying it in application-level programming. The presentation here is bottom-up and gradual, but it provides a complete look at the entire language, in isolation from its application roles.
For some, “learning Python” involves spending an hour or two going through a tutorial on the Web. This works for already advanced programmers, up to a point; Python is, after all, relatively simple in comparison to other languages. The problem with this fast-track approach is that its practitioners eventually stumble onto unusual cases and get stuck—variables change out from under them, mutable default arguments mutate inexplicably, and so on. The goal here is instead to provide a solid grounding in Python fundamentals, so that even the unusual cases will make sense when they crop up.
This scope is deliberate. By restricting our gaze to language fundamentals, we can investigate them here in more satisfying depth. Other texts, described ahead, pick up where this book leaves off and provide a more complete look at application-level topics and additional reference materials. The purpose of the book you are reading now is solely to teach Python itself so that you can apply it to whatever domain you happen to work in.
About This Book
This section underscores some important points about this book in general, regardless of its edition number. No book