PHP and MySQL for Dynamic Web Sites: Visual QuickPro Guide, Fifth Edition

14. Perl-Compatible Regular Expressions

In This Chapter

Creating a Test Script

Defining Simple Patterns

Using Quantifiers

Using Character Classes

Finding All Matches

Using Modifiers

Matching and Replacing Patterns

Review and Pursue

Regular expressions are an amazingly powerful—but often taxing—tool available in most of today’s programming languages and even in many applications. Think of regular expressions as an elaborate system of matching patterns. You first write the pattern and then use one of PHP’s built-in functions to apply the pattern to a value (regular expressions are applied to strings, even if that means a string with a numeric value). Whereas a string function could see if the name John is in some text, a regular expression could ...