This O'Reilly Cookbook provides more than a hundred recipes to help programmers use regular expressions to manipulate text and crunch data. Every programmer needs a grasp of regular expressions, but their power doesn't come without problems--even seasoned users often have trouble tackling performance issues. With recipes for popular programming languages such as C#, Java, JavaScript, Perl, PHP, Python, Ruby, and VB.NET, this book offers step-by-step solutions to scores of common tasks involving regular expressions. This cookbook will help you: Understand the basics of regular expressions through a concise tutorial Use regular expressions effectively in several programming and scripting languages Learn how to validate and format input Manage words, lines, special characters, and numerical values Find solutions for using regular expressions in URLs, paths, markup, and data exchange Learn the nuances of more advanced regex features Understand how regular expression APIs differ from language to language Write better regular expressions for custom needs Whether you're a novice or an experienced user, Regular Expressions Cookbook will help deepen your understanding of this tool. You'll learn powerful new tricks, avoid language-specific gotchas, and save valuable time with this huge library of proven solutions to difficult, real-world problems.