Dive Into Python 3

Title page

Copyright Page

Contents at a Glance

Table of Contents

Foreword

About the Author

About the Technical Reviewer

Acknowledgments

Installing Python

Which Python Is Right for You?

Installing on Microsoft Windows

Installing on Mac OS X

Installing on Ubuntu Linux

Installing on Other Platforms

Using the Python Shell

Python Editors and IDEs

CHAPTER 1 Your First Python Program

Declaring Functions

Optional and Named Arguments

Writing Readable Code

Documentation Strings

The import Search Path

Everything Is an Object

What’s an Object?

Indenting Code

Exceptions

Catching Import Errors

Unbound Variables

Running Scripts

Further Reading Online

CHAPTER 2 Native Datatypes

Booleans

Numbers

Coercing Integers to Floats and Vice Versa

Common Numerical Operations

Fractions

Trigonometry

Numbers in a Boolean Context

Lists

Creating a List

Slicing a List

Adding Items to a List

Searching For Values in a List

Removing Items from a List

Removing Items from a List: Bonus Round

Lists in a Boolean Context

Tuples

Tuples in a Boolean Context

Assigning Multiple Values at Once

Sets

Modifying a Set

Removing Items from a Set

Common Set Operations

Sets in a Boolean Context

Dictionaries

Creating a Dictionary

Modifying a Dictionary

Mixed-Value Dictionaries

Dictionaries in a Boolean Context

None

None in a Boolean Context

Further Reading Online

CHAPTER 3 Comprehensions

Working With Files and Directories

The Current Working Directory

Working with Filenames and Directory Names

Listing Directories

Getting File Metadata

Constructing Absolute Pathnames

List Comprehensions

Dictionary Comprehensions

Fun with Dictionary Comprehensions

Set Comprehensions

Further Reading Online

CHAPTER 4 Strings

Unicode

Diving In

Formatting Strings

Compound Field Names

Format Specifiers

Other Common String Methods

Slicing a String

Strings versus Bytes

Character Encoding of Python Source Code

Further Reading Online

CHAPTER 5 Regular Expressions

Case Study: Street Addresses

Case Study: Roman Numerals

Checking for Thousands

Checking for Hundreds

Using the {n,m} Syntax

Checking for Tens and Ones

Verbose Regular Expressions

Case Study: Parsing Phone Numbers

Further Reading Online

CHAPTER 6 Closures and Generators

I Know, Let’s Use Regular Expressions!

A List of Functions

A List of Patterns

A File of Patterns

Generators

A Fibonacci Generator

A Plural Rule Generator

Further Reading Online

CHAPTER 7 Classes and Iterators

Defining Classes

The __init__() Method

Instantiating Classes

Instance Variables

A Fibonacci Iterator

A Plural Rule Iterator

Further Reading Online

CHAPTER 8 Advanced Iterators

Finding All Occurrences of a Pattern

Finding the Unique Items in a Sequence

Making Assertions

Generator Expressions

Calculating Permutations … the Lazy Way

Other Fun Stuff in the itertools Module

A New Kind of String Manipulation

Evaluating Arbitrary Strings as Python Expressions

Putting It All Together

Further Reading Online

CHAPTER 9 Unit Testing

A Single Question

Halt and Catch Fire

More Halting, More Fire

And One More Thing …

A Pleasing Symmetry

More Bad Input

CHAPTER 10 Refactoring

Handling Changing Requirements

Refactoring

Further Reading Online

CHAPTER 11 Files

Reading from Text Files

Character Encoding Rears Its Ugly Head

Stream Objects

Reading Data from a Text File

Closing Files

Closing Files Automatically

Reading Data One Line at a Time

Writing to Text Files

Character Encoding Again

Binary Files

Streams Objects from Nonfile Sources

Handling Compressed Files

Standard Input, Output, and Error

Redirecting Standard Output

Further Reading Online

CHAPTER 12 XML

A 5-Minute Crash Course in XML

The Structure of an Atom Feed

Parsing XML

Elements Are Lists

Attributes Are Dictionaries

Searching for Nodes Within an XML Document

Going Further with lxml

Generating XML

Parsing Broken XML

Further Reading Online

CHAPTER 13 Serializing Python Objects

A Quick Note About the Examples in this Chapter

Saving Data to a Pickle File

Loading Data from a Pickle File

Pickling Without a File

Bytes and Strings Rear Their Ugly Heads Again

Debugging Pickle Files

Serializing Python Objects to be Read by Other Languages

Saving Data to a JSON File

Mapping Python Datatypes to JSON

Serializing Datatypes Unsupported by JSON

Loading Data from a JSON File

Further Reading Online

CHAPTER 14 HTTP Web Services

Features of HTTP

Caching

Last-Modified Checking

ETags

Compression

Redirects

How Not to Fetch Data Over HTTP

What’s On the Wire?

Introducing httplib2

Caching with httplib2

Handling Last-Modified and ETag Headers with httplib2

Handling Compression with httplib2

Handling Redirects with httplib2

Beyond HTTP GET

Beyond HTTP POST

Further Reading Online

CHAPTER 15 Case Study: Porting chardet to Python 3

What Is Character Encoding Auto-Detection?

Why Auto-Detection Is Difficult

Auto-Encoding Algorithms

Introducing the chardet Module

UTF-n with a BOM

Escaped Encodings

Multibyte Encodings

Single-Byte Encodings

windows-1252

Running 2to3

A Short Digression Into Multi-File Modules

Fixing What 2to3 Can’t

False Is Invalid Syntax

No Module Named Constants

Name 'file' Is Not Defined

Can’t Use a String Pattern on a Bytes-Like Object

Can’t Convert 'bytes' Object to str Implicitly

Unsupported Operand type(s) for +: 'int' and 'bytes'

ord() Expected String of Length 1, but int Found

Unorderable Types: int() >= str()

Global Name 'reduce' Is not Defined

Lessons Learned

CHAPTER 16 Packaging Python Libraries

Things Distutils Can’t Do for You

Directory Structure

Writing Your Setup Script

Classifying Your Package

Examples of Good Package Classifiers

Checking Your Setup Script for Errors

Creating a Source Distribution

Creating a Graphical Installer

Building Installable Packages for Other Operating Systems

Adding Your Software to the Python Package Index

The Many Possible Futures of Python Packaging

Further Reading Online

APPENDIX A Porting Code to Python 3 with 2to3

print Statement

Unicode String Literals

unicode() Global Function

long Datatype

<> Comparison

has_key() Dictionary Method

Dictionary Methods that Return Lists

Renamed or Reorganized Modules

http

urllib

dbm

xmlrpc

Other Modules

Relative Imports Within a Package

next() Iterator Method

filter() Global Function

map() Global Function

reduce() Global Function

apply() Global Function

intern() Global Function

exec Statement

execfile Statement

repr Literals (Backticks)

try...except Statement

raise Statement

throw Method on Generators

xrange() Global Function

raw_input() and input() Global Functions

func_* Function Attributes

xreadlines() I/O Method

lambda Functions that Take a Tuple Instead of Multiple Parameters

Special Method Attributes

__nonzero__ Special Method

Octal Literals

sys.maxint

callable() Global Function

zip() Global Function

StandardError Exception

types Module Constants

isinstance() Global Function

basestring Datatype

itertools Module

sys.exc_type, sys.exc_value, sys.exc_traceback

List Comprehensions Over Tuples

os.getcwdu() Function

Metaclasses

Matters of Style

set() Literals (Explicit)

buffer() Global Function (Explicit)

Whitespace Around Commas (Explicit)

Common Idioms (Explicit)

APPENDIX B Special Method Names

Basics

Classes that Act Like Iterators

Computed Attributes

Classes that Act Like Functions

Classes that Act Like Sequences

Classes that Act Like Dictionaries

Classes that Act Like Numbers

Classes that Can Be Compared

Classes that Can Be Serialized

Classes that Can Be Used in a “with” Block

Really Esoteric Stuff

Further Reading Online

APPENDIX C Where to Go From Here

Index