Page 20 - Beginning PHP 5.3

Contents
Manipulating Arrays 121
Sorting Arrays 121
Adding and Removing Array Elements 128
Merging Arrays Together 134
Converting Between Arrays and Strings 136
Converting an Array to a List of Variables 137
Summary 138
Exercises 139

Chapter 7: Functions 141

What Is a Function? 141
Why Functions Are Useful 142
Calling Functions 142
Working with Variable Functions 144
Writing Your Own Functions 145
Defining Parameters 145
Optional Parameters and Default Values 147
Returning Values from Your Functions 148
Understanding Variable Scope 150
Creating Anonymous Functions 154
Working with References 158
Passing References to Your Own Functions 159
Returning References from Your Own Functions 160
Writing Recursive Functions 160
Summary 163
Exercises 164

Chapter 8: Objects 165

What Is Object-Oriented Programming? 166
Advantages of OOP 166
Understanding Basic OOP Concepts 167
Classes 167
Objects 167
Properties 168
Methods 168
Creating Classes and Objects in PHP 168
Creating and Using Properties 169
Understanding Property Visibility 169
Declaring Properties 170
Accessing Properties 170

xviii

9/21/09 2:46:42 PM
ftoc.indd xviii
ftoc.indd xviii 9/21/09 2:46:42 PM