PHP 5 Unleashed

Chapter 3. Regular Expressions

IN THIS CHAPTER

• The Basics of Regular Expressions

• Limitations of the Basic Syntax

• POSIX Regular Expressions

• Perl-Compatible Regular Expressions (PCRE)

• PCRE Modifiers

Regular expressions (regex) are one of the black arts of practical computer programming. Ask any programmer, and chances are that he or she will, at some point, have had serious problems with them (or, even worse, avoided them altogether).

Yet, regular expressions, although complicated, are not really difficult to understand. Fundamentally, they are a way to describe patterns of text using a single set of strings. Unlike a simple search-and-replace operation, such as changing all instances of “Marco” with “Tabini,” regex allows for much more flexibility—for ...