Roses Are Red, Violets Are Blue; Lists Are Mutable, and So Is Class Foo

Data structures are a central theme in most programs, whether you know it or not. It may not always be obvious, because Python provides a set of built-in types that make it easy to deal with structured data: lists, strings, tuples, dictionaries, and the like. For simple systems, these types are usually enough. Technically, dictionaries make many of the classical searching algorithms unnecessary in Python, and lists replace much of the work you'd do to support collections in lower-level languages. Both are so easy to use, though, that you generally never give them a second thought.

But for advanced applications, we may need to add more sophisticated types of our own to handle extra requirements. In this chapter, we'll explore a handful of advanced data structure implementations in Python: sets, stacks, graphs, and so on. As we'll see, data structures take the form of new object types in Python, integrated into the language's type model. That is, objects we code in Python become full-fledged datatypes -- they can look and feel just like built-in lists, numbers, and dictionaries, to the scripts that use them.

Although the examples in this chapter illustrate advanced programming techniques, they also underscore Python's support for writing reusable software. By coding object implementations with classes, modules, and other Python tools, they naturally become generally useful components, which may be used in any program that imports them. In effect, we will be building libraries of data structure classes, whether we plan for it or not.

In addition, although the examples in this chapter are pure Python code, we will also be building a path towards the next part of the book here. From the most general perspective, new Python objects can be implemented in either Python or an integrated language such as C. In particular, pay attention to the stack objects implemented in the first section of this chapter; they will later be reimplemented in C to gauge both the benefits and complexity of C migration.

Introducing Python

Part I: System Interfaces

System Tools

Parallel System Tools

Larger System Examples I

Larger System Examples II

Part II: GUI Programming

Graphical User Interfaces

A Tkinter Tour, Part 1

A Tkinter Tour, Part 2

Larger GUI Examples

Part III: Internet Scripting

Network Scripting

Client-Side Scripting

Server-Side Scripting

Larger Web Site Examples I

Larger Web Site Examples II

Advanced Internet Topics

Part IV: Assorted Topics

Databases and Persistence

Data Structures

Text and Language

Part V: Integration

Extending Python

Embedding Python

VI: The End

Conclusion Python and the Development Cycle

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Programming Python
Python Programming for the Absolute Beginner, 3rd Edition
ISBN: 1435455002
EAN: 2147483647
Year: 2000
Pages: 245
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