Book Image

Java 9 Regular Expressions

By : Anubhava Srivastava
Book Image

Java 9 Regular Expressions

By: Anubhava Srivastava

Overview of this book

Regular expressions are a powerful tool in the programmer's toolbox and allow pattern matching. They are also used for manipulating text and data. This book will provide you with the know-how (and practical examples) to solve real-world problems using regex in Java. You will begin by discovering what regular expressions are and how they work with Java. This easy-to-follow guide is a great place from which to familiarize yourself with the core concepts of regular expressions and to master its implementation with the features of Java 9. You will learn how to match, extract, and transform text by matching specific words, characters, and patterns. You will learn when and where to apply the methods for finding patterns in digits, letters, Unicode characters, and string literals. Going forward, you will learn to use zero-length assertions and lookarounds, parsing the source code, and processing the log files. Finally, you will master tips, tricks, and best practices in regex with Java.
Table of Contents (15 chapters)
Title page
About the Author
About the Reviewer
Customer Feedback
Free Chapter
Getting Started with Regular Expressions

Chapter 2. Understanding the Core Constructs of Java Regular Expressions

Using Java as a regular expression flavor, in this chapter, we will go a bit deeper and learn in detail about anchors, quantifiers, boundary matchers, all the available character classes, negated character classes, predefined character classes, and character classes escaping rules, using Java as a reference point. You will also learn Unicode text matching, using regular expressions in Java. We will also cover greedy versus non-greedy (lazy matching) and the change of regular expression behavior with lazy matching.

We will cover the following topics in this chapter:

  • Anchors and quantifiers
  • Boundary matchers
  • Character classes
  • Regex escaping rules
  • Escaping inside character classes
  • Negated character classes
  • Predefined character classes
  • Unicode characters matching
  • Greedy quantifiers
  • Lazy quantifiers
  • Possessive quantifiers
  • Various embedded modes in regular expressions and their meaning
  • Enabling/disabling regular expression modes inside...