第8页 | Learning Python | 阅读 ‧ 电子书库

New Chapters

Although the main purpose of this edition is to update the examples and material from the preceding edition for 3.0 and 2.6, I’ve also added five new chapters to address new topics and add context:

 

Chapter 27 is a new class tutorial, using a more realistic example to explore the basics of Python object-oriented programming (OOP). Chapter 36 provides details on Unicode and byte strings and outlines string and file differences between 3.0 and 2.6. Chapter 37 collects managed attribute tools such as properties and provides new coverage of descriptors. Chapter 38 presents function and class decorators and works through comprehensive examples. Chapter 39 covers metaclasses and compares and contrasts them with decorators.

The first of these chapters provides a gradual, step-by-step tutorial for using classes and OOP in Python. It’s based upon a live demonstration I have been using in recent years in the training classes I teach, but has been honed here for use in a book. The chapter is designed to show OOP in a more realistic context than earlier examples and to illustrate how class concepts come together into larger, working programs. I hope it works as well here as it has in live classes.

The last four of these new chapters are collected in a new final part of the book, “Advanced Topics.” Although these are technically core language topics, not every Python programmer needs to delve into the details of Unicode text or metaclasses. Because of this, these four chapters have been separated out into this new part, and are officially optional reading. The details of Unicode and binary data strings, for example, have been moved to this final part because most programmers use simple ASCII strings and don’t need to know about these topics. Similarly, decorators and metaclasses are specialist topics that are usually of more interest to API builders than application programmers.

If you do use such tools, though, or use code that does, these new advanced topic chapters should help you master the basics. In addition, these chapters’ examples include case studies that tie core language concepts together, and they are more substantial than those in most of the rest of the book. Because this new part is optional reading, it has end-of-chapter quizzes but no end-of-part exercises.