Perl语言入门 原书第6版PDF电子书下载

1．Introduction 1

Questions and Answers 1

Is This the Right Book for You? 1

Why Are There So Many Footnotes? 2

What About the Exercises and Their Answers? 3

What Do Those Numbers Mean at the Start of the Exercise? 4

What If I'm a Perl Course Instructor? 4

What Does"Perl"Stand For? 4

Why Did Larry Create Perl? 5

Why Didn't Larry Just Use Some Other Language? 5

Is Perl Easy or Hard? 6

How Did Perl Get to Be So Popular? 7

What's Happening with Perl Now? 7

What's Perl Really Good For? 8

What Is Perl Not Good For? 8

How Can I Get Perl? 9

What Is CPAN? 10

How Can I Get Support for Perl? 10

Are There Any Other Kinds of Support? 10

What If I Find a Bug in Perl? 12

How Do I Make a Perl Program? 12

A Simple Program 13

What's Inside That Program? 15

How Do I Compile My Perl Program? 16

A Whirlwind Tour of Perl 17

Exercises 18

2．Scalar Data 21

Numbers 21

All Numbers Have the Same Format Internally 22

Floating-Point Literals 22

Integer Literals 22

Nondecimal Integer Literals 23

Numeric Operators 23

Strings 24

Single-Quoted String Literals 25

Double-Quoted String Literals 25

String Operators 26

Automatic Conversion Between Numbers and Strings 27

Perl's Built-in Warnings 28

Scalar Variables 29

Choosing Good Variable Names 30

Scalar Assignment 31

Binary Assignment Operators 31

Output with print 32

Interpolation of Scalar Variables into Strings 32

Creating Characters by Code Point 34

Operator Precedence and Associativity 34

Comparison Operators 36

The if Control Structure 37

Boolean Values 38

Getting User Input 39

The chomp Operator 39

The while Control Structure 40

The undef Value 41

The defined Function 42

Exercises 42

3．Lists and Arrays 43

Accessing Elements of an Array 44

Special Array Indices 45

List Literals 46

The qw Shortcut 46

List Assignment 48

The pop and push Operators 49

The shift and unshift Operators 50

The splice Operator 50

Interpolating Arrays into Strings 51

The foreach Control Structure 53

Perl's Favorite Default:$_ 54

The reverse Operator 54

The sort Operator 54

The each Operator 55

Scalar and List Context 55

Using List-Producing Expressions in Scalar Context 57

Using Scalar-Producing Expressions in List Context 58

Forcing Scalar Context 59

＜STDIN＞in List Context 59

Exercises 60

4．Subroutines 63

Defining a Subroutine 63

Invoking a Subroutine 64

Return Values 64

Arguments 66

Private Variables in Subroutines 68

Variable-Length Parameter Lists 69

A Better＆max Routine 69

Empty Parameter Lists 70

Notes on Lexical(my)Variables 71

The use strict Pragma 72

The return Operator 74

Omitting the Ampersand 74

Non-Scalar Return Values 76

Persistent,Private Variables 76

Exercises 78

5．Input and Output 81

Input from Standard Input 81

Input from the Diamond Operator 83

The Invocation Arguments 85

Output to Standard Output 86

Formatted Output with printf 89

Arrays and printf 90

Filehandles 91

Opening a Filehandle 93

Binmoding Filehandles 95

Bad Filehandles 96

Closing a Filehandle 96

Fatal Errors with die 97

Warning Messages with warn 99

Automatically die-ing 99

Using Filehandles 100

Changing the Default Output Filehandle 100

Reopening a Standard Filehandle 101

Output with say 102

Filehandles in a Scalar 103

Exercises 104

6．Hashes 107

What Is a Hash? 107

Why Use a Hash? 109

Hash Element Access 110

The Hash As a Whole 112

Hash Assignment 113

The Big Arrow 114

Hash Functions 115

The keys and values Functions 115

The each Function 116

Typical Use of a Hash 118

The exists Function 118

The delete Function 118

Hash Element Interpolation 119

The ％ENV hash 119

Exercises 120

7．In the World of Regular Expressions 121

What Are Regular Expressions? 121

Using Simple Patterns 122

Unicode Properties 123

About Metacharacters 123

Simple Quantifiers 124

Grouping in Patterns 125

Alternatives 127

Character Classes 128

Character Class Shortcuts 129

Negating the Shortcuts 131

Exercises 131

8．Matching with Regular Expressions 133

Matches with m// 133

Match Modifiers 134

Case-Insensitive Matching with/i 134

Matching Any Character with/s 134

Adding Whitespace with/x 135

Combining Option Modifiers 135

Choosing a Character Interpretation 136

Other Options 138

Anchors 138

Word Anchors 140

The Binding Operator=～ 141

Interpolating into Patterns 142

The Match Variables 143

The Persistence of Captures 144

Noncapturing Parentheses 145

Named Captures 146

The Automatic Match Variables 147

General Quantifiers 149

Precedence 150

Examples of Precedence 151

And There's More 152

A Pattern Test Program 152

Exercises 153

9．Processing Text with Regular Expressions 155

Substitutions with s/// 155

Global Replacements with/g 156

Different Delimiters 157

Substitution Modifiers 157

The Binding Operator 157

Nondestructive Substitutions 157

Case Shifting 158

The split Operator 159

The join Function 160

m//in List Context 161

More Powerful Regular Expressions 161

Nongreedy Quantifiers 162

Matching Multiple-Line Text 164

Updating Many Files 164

In-Place Editing from the Command Line 166

Exercises 168

10．More Control Structures 169

The unless Control Structure 169

The else Clause with unless 170

The until Control Structure 170

Expression Modifiers 171

The Naked Block Control Structure 172

The elsif Clause 173

Autoincrement and Autodecrement 174

The Value of Autoincrement 175

The for Control Structure 176

The Secret Connection Between foreach and for 178

Loop Controls 178

The last Operator 179

The next Operator 179

The redo Operator 181

Labeled Blocks 182

The Conditional Operator?: 182

Logical Operators 184

The Value of a Short Circuit Operator 184

The defined-or Operator 185

Control Structures Using Partial-Evaluation Operators 186

Exercises 188

11．Perl Modules 189

Finding Modules 189

Installing Modules 190

Using Your Own Directories 191

Using Simple Modules 193

The File::Basename Module 194

Using Only Some Functions from a Module 195

The File::Spec Module 196

Path::Class 197

CGI.pm 198

Databases and DBI 199

Dates and Times 200

Exercises 201

12．File Tests 203

File Test Operators 203

Testing Several Attributes of the Same File 207

Stacked File Test Operators 208

The stat and lstat Functions 210

The localtime Function 211

Bitwise Operators 212

Using Bitstrings 213

Exercises 214

13．Directory Operations 215

Moving Around the Directory Tree 215

Globbing 216

An Alternate Syntax for Globbing 217

Directory Handles 218

Recursive Directory Listing 220

Manipulating Files and Directories 221

Removing Files 221

Renaming Files 223

Links and Files 224

Making and Removing Directories 229

Modifying Permissions 230

Changing Ownership 231

Changing Timestamps 231

Exercises 232

14．Strings and Sorting 235

Finding a Substring with index 235

Manipulating a Substring with substr 236

Formatting Data with sprintf 238

Using sprintf with"Money Numbers" 238

Interpreting Non-Decimal Numerals 240

Advanced Sorting 240

Sorting a Hash by Value 244

Sorting by Multiple Keys 245

Exercises 246

15．Smart Matching and given-when 247

The Smart MaTch Operator 247

Smart Match Precedence 250

The given Statement 251

Dumb Matching 254

Using when with Many Items 256

Exercises 257

16．Process Management 259

The system Function 259

Avoiding the Shell 261

The Environment Variables 263

The exec Function 263

Using Backquotes to Capture Output 264

Using Backquotes in a List Context 267

External Processes with IPC::System::Simple 268

Processes as Filehandles 269

Getting Down and Dirty with Fork 271

Sending and Receiving Signals 272

Exercises 274

17．Some Advanced Perl Techniques 277

Slices 277

Array Slice 279

Hash Slice 281

Trapping Errors 282

Using eval 282

More Advanced Error Handling 286

autodie 288

Picking Items from a List with grep 289

Transforming Items from a List with map 290

Fancier List Utilities 291

Exercises 293

A．Exercise Answers 295

B．Beyond the Llama 331

C．A Unicode Primer 343

Index 353