PHP 5 Recipes: A Problem-solution Approach

673 Pages·2005·5.392 MB·English

by  Frank M. Kromann, Jon Stephens, Nathan A. Good, Lee Babin

5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page i
PHP 5 Recipes
A Problem-Solution Approach
Lee Babin, Nathan A. Good,
Frank M. Kromann, Jon Stephens
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page ii
PHP 5 Recipes: A Problem-Solution Approach
Copyright © 2005 by Lee Babin,Nathan A.Good,Frank M.Kromann,Jon Stephens
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information storage or retrieval
system, without the prior written permission of the copyright owner and the publisher.
ISBN (pbk): 1-59059-509-2
Printed and bound in the United States of America 9 8 7 6 5 4 3 2 1
Trademarked names may appear in this book. Rather than use a trademark symbol with every occurrence
of a trademarked name, we use the names only in an editorial fashion and to the benefit of the trademark
owner, with no intention of infringement of the trademark.
Lead Editor: Chris Mills
Technical Reviewer: Rob Kunkle
Editorial Board: Steve Anglin, Dan Appleman, Ewan Buckingham, Gary Cornell, Tony Davis,
Jason Gilmore, Jonathan Hassell, Chris Mills, Dominic Shakeshaft, Jim Sumser
Associate Publisher: Grace Wong
Project Manager: Kylie Johnston
Copy Edit Manager: Nicole LeClerc
Copy Editor: Kim Wimpsett
Assistant Production Director: Kari Brooks-Copony
Production Editor: Katie Stence
Compositor and Artist: Van Winkle Design Group
Proofreader: April Eddy
Indexer: Broccoli Information Management
Interior Designer: Van Winkle Design Group
Cover Designer: Kurt Krames
Manufacturing Manager: Tom Debolski
Distributed to the book trade worldwide by Springer-Verlag New York, Inc., 233 Spring Street, 6th Floor,
New York, NY 10013. Phone 1-800-SPRINGER, fax [phone], e-mail [email protected], or
visit http://www.springeronline.com.
For information on translations, please contact Apress directly at 2560 Ninth Street, Suite 219, Berkeley,
CA 94710. Phone [phone], fax [phone], e-mail [email protected], or visit http://www.apress.com.
The information in this book is distributed on an “as is” basis, without warranty. Although every precaution
has been taken in the preparation of this work, neither the author(s) nor Apress shall have any liability to any
person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by
the information contained in this work.
The source code for this book is available to readers at http://www.apress.comin the Source Code section.
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page iii
Contents at a Glance
About the Authors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
About the Technical Reviewer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
■ CHAPTER 1 Overview of PHP Data Types and Concepts . . . . . . . . . . . . . . . . . . . . . . 1
■ CHAPTER 2 Overview of Classes,Objects,and Interfaces . . . . . . . . . . . . . . . . . . . 21
■ CHAPTER 3 Performing Math Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
■ CHAPTER 4 Working with Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
■ CHAPTER 5 Working with Dates and Times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
■ CHAPTER 6 Working with Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
■ CHAPTER 7 Working with Files and Directories. . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
■ CHAPTER 8 Working with Dynamic Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
■ CHAPTER 9 Using Regular Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
■ CHAPTER 10 Working with Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
■ CHAPTER 11 Using Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
■ CHAPTER 12 Understanding Web Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
■ CHAPTER 13 Creating and Using Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
■ CHAPTER 14 Working with Markup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
■ CHAPTER 15 Using MySQL Databases in PHP 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
■ CHAPTER 16 Communicating with Internet Services . . . . . . . . . . . . . . . . . . . . . . . . 597
■ INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
iii
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page iv
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page v
Contents
About the Authors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
About the Technical Reviewer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
■ CHAPTER 1 Overview of PHP Data Types and Concepts . . . . . . . . . . . . . . . . 1
1-1.Variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1-2.Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1-3.Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1-4.Strings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1-5.Regular Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1-6.Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1-7.Project:Finding the Data Type of a Value. . . . . . . . . . . . . . . . . . . . . . . 10
1-8.Project:Discovering What Variables,Constants,
Functions,Classes,and Interfaces Are Available . . . . . . . . . . . . . . . . . . 12
1-9.Getting Information About the Current Script. . . . . . . . . . . . . . . . . . . . 14
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
■ CHAPTER 2 Overview of Classes,Objects,and Interfaces. . . . . . . . . . . . . 21
Understanding Basic Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2-1.Creating Instances Using Constructors. . . . . . . . . . . . . . . . . . . . . . . . . 24
2-2.Using Default Constructors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2-3.Setting Object Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2-4.Controlling Access to Class Members. . . . . . . . . . . . . . . . . . . . . . . . . . 30
2-5.Using Static Members and the self Keyword. . . . . . . . . . . . . . . . . . . . 33
2-6.Using Class Constants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2-7.Extending Classes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2-8.Using Abstract Classes and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2-9.Using Interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2-10.Using Class Destructors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
2-11.Using Exceptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Getting Information About Classes and Objects. . . . . . . . . . . . . . . . . . . . . . 61
Using Class and Object Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
v
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page vi
vi ■ CONTENTS
2-12.Checking for the Existence of Classes and
Interfaces Using class_exists() and interface_exists(). . . . . . . . . . . . . . 63
2-13.Listing Methods and Interfaces Using get_class_methods(). . . . . . . 65
2-14.Obtaining Variable Names. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
2-15.Determining Whether an Object Is an Instance
of a Particular Class. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
2-16.Listing Currently Loaded Interfaces and Classes . . . . . . . . . . . . . . . 69
Using the Class Reflection API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
2-17.Obtaining a Dump of the Reflection API . . . . . . . . . . . . . . . . . . . . . . . 73
2-18.Performing Dynamic Class Instantiation. . . . . . . . . . . . . . . . . . . . . . . 76
2-19.Using the Reflection API to Deconstruct the Shape Class. . . . . . . . 77
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
■ CHAPTER 3 Performing Math Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
3-1.Numeric Data Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
3-2.Random Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
3-3.Logarithms and Exponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
3-4.Trigonometric Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3-5.Formatting of Numeric Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
3-6.Math Libraries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
3-7.A Static Math Class. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
■ CHAPTER 4 Working with Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
4-1.Creating Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
4-2.Accessing Array Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
4-3.Creating Multidimensional Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
4-4.Using Array Keys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
4-5.Initializing an Array As a Range or Sequence of Values. . . . . . . . . . 124
Outputting Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
4-6.Outputting an Array As a String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
4-7.Outputting Using array_values() and array_keys()
for Backward Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
4-8.Outputting an Array As a Tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Adding New Elements to Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
4-9.Adding an Element to the End of an Array . . . . . . . . . . . . . . . . . . . . . 131
4-10.Appending One Array to Another . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
4-11.Comparing Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page vii
■ CONTENTS vii
4-12.Adding an Element to the Beginning of an Array. . . . . . . . . . . . . . . 137
4-13.Inserting New Values at an Arbitrary Point
in an Indexed Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Getting and Setting the Size of an Array. . . . . . . . . . . . . . . . . . . . . . . . . . . 139
4-14.Counting Array Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
4-15.Setting an Array’s Size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Traversing Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
4-16.Looping Through an Associative Array Using foreach. . . . . . . . . . . 144
4-17.Looping Through a Compact Indexed Array
Using for and count(). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
4-18.Looping Through a Sparse Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Removing Elements from Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
4-19.Removing the First or Last Element from an Array. . . . . . . . . . . . . 148
4-20.Removing One or More Arbitrary Array Elements. . . . . . . . . . . . . . 150
4-21.Extracting a Portion of an Array. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4-22.Extracting Values from Arrays with extract() . . . . . . . . . . . . . . . . . . 154
4-23.Extracting Values from an Array Using list(). . . . . . . . . . . . . . . . . . . 156
4-24.Combining Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
4-25.Obtaining Array Keys and Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
4-26.Working with Unique Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
4-27.Getting and Displaying Counts of Array Values . . . . . . . . . . . . . . . . 161
Finding and Working with Array Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
4-28.Determining Whether an Element Is in an Array. . . . . . . . . . . . . . . 163
4-29.Testing for the Existence of a Key in an Array. . . . . . . . . . . . . . . . . 164
4-30.Obtaining Array Keys with a Given Value . . . . . . . . . . . . . . . . . . . . . 165
4-31.Finding the Greatest and Least Values in an Array. . . . . . . . . . . . . 166
4-32.Finding the Sum and Average of the Values in an Array . . . . . . . . 168
Applying Functions to Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
4-33.Applying Functions to Array Elements Using array_walk() . . . . . . 170
4-34.Applying Functions to Array Elements Using array_map(). . . . . . . 173
4-35.Filtering Arrays Using array_filter() . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Sorting Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
4-36.Sorting an Array by Its Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
4-37.Sorting an Array by Its Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
4-38.Reversing an Array Using arsort() . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
4-39.Reversing an Array Using krsort() . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
4-40.Reversing an Array Using array_reverse() . . . . . . . . . . . . . . . . . . . . 182
4-41.Randomizing an Array Using shuffle(),kshuffle(),
and array_rand(). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
4-42.Sorting an Array Using Comparison Functions . . . . . . . . . . . . . . . . 184
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page viii
viii ■ CONTENTS
4-43.Sorting Multidimensional Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
4-44.Sorting Multiple Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Finding Permutations and Combinations. . . . . . . . . . . . . . . . . . . . . . . . . . . 190
4-45.Finding All Permutations of an Array’s Elements. . . . . . . . . . . . . . . 190
4-46.Finding All Combinations of an Array’s Elements . . . . . . . . . . . . . . 193
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
■ CHAPTER 5 Working with Dates and Times . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Overview of PHP 5’s Date and Time Functions. . . . . . . . . . . . . . . . . . . . . . 198
Displaying Dates and Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
5-1.Displaying Human-Readable Dates and Times . . . . . . . . . . . . . . . . . 201
5-2.Displaying Arbitrary Dates and Times. . . . . . . . . . . . . . . . . . . . . . . . . 204
5-3.Converting Human-Readable Dates Into Unix
Timestamps Using strtotime() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
5-4.Finding the Date for a Weekday. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
5-5.Getting the Day and Week of the Year. . . . . . . . . . . . . . . . . . . . . . . . . 211
5-6.Determining Whether a Given Year Is a Leap Year. . . . . . . . . . . . . . . 213
5-7.Getting Times and Dates of Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
5-8.Setting Time Zones and GMT/UTC. . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
5-9.Displaying Times and Dates in Other Languages . . . . . . . . . . . . . . . 219
5-10.Generating Localized GMT/UTC Time and Date Strings. . . . . . . . . 224
5-11.Obtaining the Difference Between Two Dates. . . . . . . . . . . . . . . . . 225
5-12.Project:Constructing and Using a Date Class. . . . . . . . . . . . . . . . . 231
5-13.Extending the Date Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
■ CHAPTER 6 Working with Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Manipulating Substrings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
6-1.Testing for Substrings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
6-2.Counting the Occurrences of a Substring. . . . . . . . . . . . . . . . . . . . . . 269
6-3.Accessing Substrings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
6-4.Using Substring Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
6-5.Replacing Substrings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Processing Strings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
6-6.Joining and Disassembling Strings. . . . . . . . . . . . . . . . . . . . . . . . . . . 273
6-7.Reversing Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
6-8.Controlling Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
6-9.Trimming Blank Spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
5092_Ch00_FM_FINAL 8/26/05 5:32 PM Page ix
■ CONTENTS ix
6-10.Wrapping Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
6-11.Checking String Length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
6-12.Comparing Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
6-13.Comparing Sound. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Project:Creating and Using a String Class. . . . . . . . . . . . . . . . . . . . . . . . . 285
6-14.Using a Page Reader Class. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
■ CHAPTER 7 Working with Files and Directories. . . . . . . . . . . . . . . . . . . . . . . 291
Working with Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
7-1.Opening Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
7-2.Reading from Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
7-3.Writing to Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
7-4.Closing Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
7-5.Reading and Writing Comma-Separated Data. . . . . . . . . . . . . . . . . . 298
7-6.Reading Fixed-Width Delimited Data. . . . . . . . . . . . . . . . . . . . . . . . . . 300
7-7.Reading and Writing Binary Data in a File . . . . . . . . . . . . . . . . . . . . . 301
7-8.Getting the Number of Lines in a File . . . . . . . . . . . . . . . . . . . . . . . . . 303
7-9.Getting the Number of Characters,Words,
or Paragraphs in a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
7-10.Project:Creating and Using a File Class. . . . . . . . . . . . . . . . . . . . . . 305
Working with Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
7-11.Listing All Files in the Current Directory. . . . . . . . . . . . . . . . . . . . . . 310
7-12.Listing All Files of a Certain Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
7-13.Sorting Files by Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
7-14.Generating a Recursive Directory Listing. . . . . . . . . . . . . . . . . . . . . 314
7-15.Using the SPL DirectoryIterator Object. . . . . . . . . . . . . . . . . . . . . . . 316
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Looking Ahead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
■ CHAPTER 8 Working with Dynamic Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Working with Image Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
8-1.Working with JPGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
8-2.Working with GIFs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
8-3.Working with PNGs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Working with Image Libraries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Creating an Image from Scratch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
8-4.Creating a Blank Canvas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
8-5.Creating and Using Colors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329