Sams Teach Yourself Perl in 21 Days

Sams Teach Yourself Perl in 21Days, Second Edition......Page 2
Copyright © 2002 by Sams Publishing......Page 3
Contents at a Glance......Page 4
Contents......Page 6
About the Authors......Page 21
Tell Us What You Think!......Page 23
Introduction......Page 24
How This Book Is Organized......Page 25
Conventions Used in This Book......Page 27
WEEK 1 Getting Started......Page 28
DAY 1 An Introduction to Perl......Page 30
What Is Perl and Where Did It Come From?......Page 31
Why Learn Perl?......Page 32
Getting Started Programming in Perl......Page 35
An Example: The Ubiquitous Hello World......Page 36
Another Example: Create Hello World As a Script......Page 38
Another Example: Echo......Page 42
A Third Example: The Cookie Monster......Page 43
Going Deeper......Page 44
Q&A......Page 46
Workshop......Page 48
Answers......Page 49
DAY 2 Working with Strings and Numbers (Scalar Data)......Page 52
Scalar Data and Scalar Variables......Page 53
Constructing Perl Scripts......Page 58
Arithmetic Operators......Page 59
One-Liners: Simple Calculator......Page 61
An Example: Converting Fahrenheit to Celsius......Page 62
Operators for Tests and Comparisons......Page 63
Another Example: More Cookies......Page 69
Going Deeper......Page 71
Summary......Page 73
Q&A......Page 74
Workshop......Page 75
Answers......Page 76
DAY 3 More Scalar Data and Operators......Page 80
Assignment Operators......Page 81
Increment and Decrement Operators......Page 82
String Concatenation and Repetition......Page 83
Operator Precedence and Associativity......Page 84
Using Patterns to Match Digits......Page 86
An Example: Simple Statistics......Page 87
Input and Output......Page 91
Another Example: Stocks......Page 95
A Note About Using Functions......Page 99
Going Deeper......Page 100
Summary......Page 102
Q&A......Page 103
Workshop......Page 104
Answers......Page 105
List Data and Variables......Page 108
Defining and Using Lists and Arrays......Page 109
An Example: More Stats......Page 119
List and Scalar Context......Page 122
Input, Output, and Lists......Page 127
Going Deeper......Page 128
Summary......Page 131
Q&A......Page 132
Workshop......Page 133
Answers......Page 134
Hashes Versus Arrays and Lists......Page 138
Defining and Using Hashes......Page 140
An Example: Frequencies in the Statistics Program......Page 145
Another Example: Alphabetical Lists of Names......Page 151
A Few More Patterns......Page 152
Yet Another Example: Stock Price Converter......Page 153
Going Deeper......Page 156
Q&A......Page 157
Workshop......Page 158
Answers......Page 159
DAY 6 Conditionals and Loops......Page 166
Complex Statements and Blocks......Page 167
Conditionals......Page 168
while Loops......Page 172
An Example: Pick a Number......Page 175
Iteration with foreach and for Loops......Page 179
Controlling Loops......Page 183
Using the $_ (default) Variable......Page 187
Input from Files with while Loops and <>......Page 188
Going Deeper......Page 190
Summary......Page 192
Q&A......Page 193
Workshop......Page 194
Answers......Page 195
DAY 7 Exploring a Few Longer Examples......Page 198
Statistics with a Better Histogram......Page 199
A Number Speller......Page 203
Text-to-HTML Converter Script......Page 205
Summary......Page 211
WEEK 2 Doing More......Page 212
DAY 8 Manipulating Lists and Strings......Page 214
Array and Hash Slices......Page 215
Sorting Lists......Page 216
Searching......Page 217
An Example: More Names......Page 219
Modifying List Elements......Page 224
Other Ways to Mess with Lists......Page 227
Manipulating Strings......Page 230
Going Deeper......Page 232
Q&A......Page 233
Workshop......Page 234
Answers......Page 235
DAY 9 Pattern Matching with Regular Expressions......Page 238
The Whys and Wherefores of Pattern Matching......Page 239
Pattern Matching Operators and Expressions......Page 240
Simple Patterns......Page 241
Matching Groups of Characters......Page 245
Matching Multiple Instances of Characters......Page 249
An Example: A Guessing Program......Page 252
More About Building Patterns......Page 256
Another Example: Counting......Page 257
Pattern Precedence......Page 258
Going Deeper......Page 259
Summary......Page 260
Workshop......Page 261
Answers......Page 262
Extracting Matches......Page 266
An Example: Extracting Attributes from HTML Tags......Page 272
Using Patterns for Search and Replace......Page 274
More About split......Page 275
Matching Patterns over Multiple Lines......Page 276
A Summary of Options and Escapes......Page 278
An Example: Image Extractor......Page 279
Going Deeper......Page 284
Q&A......Page 287
Workshop......Page 288
Answers......Page 290
DAY 11 Creating and Using Subroutines......Page 292
Defining and Calling Basic Subroutines......Page 293
An Example: Son of Stats......Page 296
Returning Values from Subroutines......Page 298
Using Local Variables in Subroutines......Page 299
Passing Values into Subroutines......Page 302
Another Example: Stats with a Menu......Page 305
Going Deeper......Page 312
Q&A......Page 315
Workshop......Page 316
Answers......Page 318
DAY 12 Debugging Perl......Page 322
Using the Debugger: A Simple Example......Page 323
Starting and Running the Debugger......Page 328
Perl Debugger Command Reference......Page 334
Using a Graphical Debugger......Page 335
Going Deeper......Page 337
Workshop......Page 338
Answers......Page 339
DAY 13 Scope, Modules, and Importing Code......Page 342
Global Variables and Packages......Page 343
Local Scope and Variables......Page 348
Using Perl Modules......Page 350
An Example: Using the Text::Wrap Module......Page 360
Using Modules from CPAN (The Comprehensive Perl Archive Network)......Page 362
Going Deeper......Page 364
Summary......Page 369
Q&A......Page 370
Workshop......Page 371
Answers......Page 372
DAY 14 Exploring a Few Longer Examples......Page 376
A Searchable Address Book (address.pl)......Page 377
A Web Log Processor (weblog.pl)......Page 387
Summary......Page 400
WEEK 3 Advanced Perl......Page 402
DAY 15 Working with Files and I/O......Page 404
An Example: Extract Subjects and Save Them......Page 411
File Tests......Page 412
A File Test Example......Page 414
Working with @ARGV and Script Arguments......Page 416
Another Example......Page 421
Going Deeper......Page 422
Summary......Page 425
Workshop......Page 426
Answers......Page 428
DAY 16 Using Perl for CGI Scripting......Page 432
How CGI Works......Page 433
Building a CGI Script, From Form to Response......Page 435
Testing the Script......Page 438
Developing CGI Scripts with CGI.pm......Page 439
An Example: Survey......Page 444
Going Deeper......Page 450
Summary......Page 453
Q&A......Page 454
Workshop......Page 455
Answers......Page 457
Managing Files......Page 460
Managing and Navigating Directories......Page 463
An Example: Creating Links......Page 467
Going Deeper......Page 468
Summary......Page 469
Workshop......Page 470
Answers......Page 471
DAY 18 Perl and the Operating System......Page 476
Unix Features in Perl......Page 477
Perl for Windows......Page 488
Going Deeper......Page 497
Summary......Page 498
Q&A......Page 499
Workshop......Page 500
Answers......Page 501
DAY 19 Working with References......Page 504
The Basics: A General Overview of How to Use References......Page 505
Using References with Subroutine Arguments and Return Values......Page 510
Other Ways of Using References......Page 515
Creating Nested Data Structures with References......Page 519
Building Data Structures with Existing Data......Page 525
Accessing Elements in Nested Data Structures......Page 527
Another Example: A Database of Artists and Their Works......Page 528
Avoiding the Use of References......Page 533
Going Deeper......Page 534
Summary......Page 536
Q&A......Page 537
Workshop......Page 538
Answers......Page 540
DAY 20 Odds and Ends......Page 546
Perl One-Liners......Page 547
Object-Oriented Programming......Page 549
An Example: Using Object-Oriented Modules......Page 557
Sockets......Page 559
POD (Plain Old Documentation) Files......Page 562
Evaluating Code On-the-Fly......Page 564
Commonly Used Modules......Page 565
Creating International Perl Scripts......Page 570
Script Security with Taint Checking......Page 571
What’s Coming in Perl 6......Page 572
Summary......Page 573
Q&A......Page 574
Workshop......Page 575
Answers......Page 576
DAY 21 Exploring a Few Longer Examples......Page 582
A Stock Portfolio Manager......Page 583
A Web-Based To Do List (todolist.pl)......Page 596
Summary......Page 610
Appendixes......Page 612
For More Information......Page 614
Perl Functions, in Alphabetical Order......Page 615
Do You Need to Install Perl?......Page 652
Obtaining Perl......Page 653
Extracting and Compiling Perl......Page 655
For More Information......Page 660
APPENDIX C Installing Perl for Windows......Page 662
Installing Perl for Windows......Page 663
Downloading the Perl Source Code......Page 665
Getting More Information......Page 666
INDEX......Page 668