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 6. Exploring Zero-Width Assertions, Lookarounds, and Atomic Groups


You will learn about zero-width assertions in Java regular expressions. We will cover various zero-width assertions and their usage patterns. We will then move on to learn the important topic of lookahead and lookbehind assertions in Java regular expressions and how to use them to solve some important problems. We will also discuss the use of atomic groups in Java regular expressions.

We will cover the following topics in this chapter:

  • Zero-width assertions
  • Previous match boundary
  • Atomic groups
  • Lookahead assertions: positive and negative
  • Lookbehind assertions: positive and negative
  • Capturing text from overlapping matches
  • Capturing groups inside lookahead and lookbehind groups
  • Lookbehind limitations in Java regular expressions