PERL语言入门 第7版 影印版PDF电子书下载

1．Introduction 1

Questions and Answers 1

Is This the Right Book for You? 1

What About the Exercises and Their Answers? 2

What If I'm a Perl Course Instructor? 3

What Does“Perl”Stand For? 4

Why Did Larry Create Perl? 4

Why Didn't Larry Just Use Some Other Language? 4

Is Perl Easy or Hard? 5

How Did Perl Get to Be So Popular? 7

What's Happening with Perl Now? 7

What's Perl Really Good For? 7

What Is Perl Not Good For? 8

How Can I Get Perl? 8

What Is CPAN? 9

Is There Any Kind of Support? 9

What If I Find a Bug in Perl? 10

How Do I Make a Perl Program? 11

A Simple Program 11

What's Inside That Program? 13

How Do I Compile My Perl Program? 15

A Whirlwind Tour of Perl 16

Exercises 17

2．Scalar Data 19

Numbers 19

All Numbers Have the Same Format Internally 20

Integer Literals 20

Nondecimal Integer Literals 21

Floating-Point Literals 21

Numeric Operators 22

Strings 23

Single-Quoted String Literals 24

Double-Quoted String Literals 24

String Operators 25

Automatic Conversion Between Numbers and Strings 26

Perl's Built-In Warnings 27

Interpreting Nondecimal Numerals 28

Scalar Variables 29

Choosing Good Variable Names 30

Scalar Assignment 31

Compound Assignment Operators 31

Output with print 32

Interpolation of Scalar Variables into Strings 32

Creating Characters by Code Point 33

Operator Precedence and Associativity 34

Comparison Operators 36

The if Control Structure 37

Boolean Values 37

Getting User Input 38

The chomp Operator 39

The while Control Structure 40

The undef Value 40

The defined Function 41

Exercises 41

3．Lists and Arrays 43

Accessing Elements of an Array 44

Special Array Indices 45

List Literals 45

The qw Shortcut 46

List Assignment 47

The pop and push Operators 49

The shift and unshift Operators 49

The splice Operator 50

Interpolating Arrays into Strings 51

The foreach Control Structure 52

Perl's Favorite Default：$ 53

The reverse Operator 53

The sort Operator 54

The each Operator 54

Scalar and List Context 55

Using List-Producing Expressions in Scalar Context 56

Using Scalar-Producing Expressions in List Context 58

Forcing Scalar Context 58

＜STDIN＞ in List Context 58

Exercises 59

4．Subroutines 61

Defining a Subroutine 61

Invoking a Subroutine 62

Return Values 62

Arguments 64

Private Variables in Subroutines 66

Variable-Length Parameter Lists 67

A Better＆max Routine 67

Empty Parameter Lists 68

Notes on Lexical（my）Variables 69

The use strict Pragma 70

The return Operator 71

Omitting the Ampersand 72

Nonscalar Return Values 74

Persistent,Private Variables 74

Subroutine Signatures 76

Exercises 78

5．Input and Output 81

Input from Standard Input 81

Input from the Diamond Operator 83

The Double Diamond 85

The Invocation Arguments 85

Output to Standard Output 86

Formatted Output with printf 89

Arrays and printf 91

Filehandles 91

Opening a Filehandle 93

Binmoding Filehandles 96

Bad Filehandles 96

Closing a Filehandle 97

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 102

Exercises 104

6．Hashes 107

What Is a Hash? 107

Why Use a Hash? 109

Hash Element Access 110

The Hash as a Whole 111

Hash Assignment 112

The Big Arrow 113

Hash Functions 114

The keys and values Functions 114

The each Function 115

Typical Use of a Hash 116

The exists Function 117

The delete Function 117

Hash Element Interpolation 118

The％ENV hash 118

Exercises 119

7．Regular Expressions 121

Sequences 121

Practice Some Patterns 123

The Wildcard 125

Quantifiers 126

Grouping in Patterns 130

Alternatives 133

Character Classes 134

Character Class Shortcuts 135

Negating the Shortcuts 137

Unicode Properties 137

Anchors 138

Word Anchors 139

Exercises 141

8．Matching with Regular Expressions 143

Matches with m// 143

Match Modifiers 144

Case-Insensitive Matching with/i 144

Matching Any Character with/s 144

Adding Whitespace with/x 145

Combining Option Modifiers 146

Choosing a Character Interpretation 146

Beginning and End-of-Line Anchors 148

Other Options 149

The Binding Operator＝～ 149

The Match Variables 150

The Persistence of Captures 151

Noncapturing Parentheses 152

Named Captures 153

The Automatic Match Variables 155

Precedence 157

Examples of Precedence 158

And There's More 158

A Pattern Test Program 159

Exercises 159

9．Processing Text with Regular Expressions 161

Substitutions with s/// 161

Global Replacements with/g 162

Different Delimiters 163

Substitution Modifiers 163

The Binding Operator 163

Nondestructive Substitutions 163

Case Shifting 164

Metaquoting 166

The split Operator 166

The join Function 168

m//in List Context 168

More Powerful Regular Expressions 169

Nongreedy Quantifiers 169

Fancier Word Boundaries 170

Matching Multiple-Line Text 172

Updating Many Files 172

In-Place Editing from the Command Line 174

Exercises 176

10．More Control Structures 177

The unless Control Structure 177

The else Clause with unless 178

The until Control Structure 178

Statement Modifiers 179

The Naked Block Control Structure 180

The elsif Clause 181

Autoincrement and Autodecrement 182

The Value of Autoincrement 182

The for Control Structure 183

The Secret Connection Between foreach and for 185

Loop Controls 186

The last Operator 186

The next Operator 187

The redo Operator 188

Labeled Blocks 189

The Conditional Operator 190

Logical Operators 191

The Value of a Short-Circuit Operator 192

The defined-or Operator 193

Control Structures Using Partial-Evaluation Operators 194

Exercises 196

11．Perl Modules 197

Finding Modules 197

Installing Modules 198

Using Your Own Directories 199

Using Simple Modules 201

The File::Basename Module 202

Using Only Some Functions from a Module 203

The File::Spec Module 204

Path::Class 205

Databases and DBI 205

Dates and Times 206

Exercises 207

12．File Tests 209

File Test Operators 209

Testing Several Attributes of the Same File 213

Stacked File Test Operators 214

The stat and lstat Functions 216

The localtime Function 217

Bitwise Operators 218

Using Bitstrings 219

Exercises 222

13．Directory Operations 223

The Current Working Directory 223

Changing the Directory 224

Globbing 225

An Alternate Syntax for Globbing 227

Directory Handles 228

Manipulating Files and Directories 229

Removing Files 230

Renaming Files 231

Links and Files 232

Making and Removing Directories 237

Modiffing Permissions 239

Changing Ownership 239

Changing Timestamps 240

Exercises 240

14．Strings and Sorting 243

Finding a Substring with index 243

Manipulating a Substring with substr 245

Formatting Data with sprintf 246

Using sprintf with“Money Numbers” 247

Advanced Sorting 248

Sorting a Hash by Value 252

Sorting by Multiple Keys 253

Exercises 254

15．Process Management 255

The system Function 255

Avoiding the Shell 258

The Environment Variables 260

The exec Function 261

Using Backquotes to Capture Output 262

Using Backquotes in a List Context 264

External Processes with IPC::System::Simple 266

Processes as Filehandles 267

Getting Down and Dirty with Fork 269

Sending and Receiving Signals 270

Exercises 273

16．Some Advanced Perl Techniques 275

Slices 275

Array Slice 277

Hash Slice 279

Key-Value Slices 280

Trapping Errors 281

Using eval 281

More Advanced Error Handling 285

Picking Items from a List with grep 287

Transforming Items from a List with map 288

Fancier List Utilities 289

Exercises 291

A．Exercise Answers 293

B．Beyond the Llama 329

C．A Unicode Primer 339

D．Experimental Features 349

Index 357