Book Image

Mastering Python Regular Expressions

Book Image

Mastering Python Regular Expressions

Overview of this book

Regular expressions are used by many text editors, utilities, and programming languages to search and manipulate text based on patterns. They are considered the Swiss army knife of text processing. Powerful search, replacement, extraction and validation of strings, repetitive and complex tasks are reduced to a simple pattern using regular expressions. Mastering Python Regular Expressions will teach you about Regular Expressions, starting from the basics, irrespective of the language being used, and then it will show you how to use them in Python. You will learn the finer details of what Python supports and how to do it, and the differences between Python 2.x and Python 3.x. The book starts with a general review of the theory behind the regular expressions to follow with an overview of the Python regex module implementation, and then moves on to advanced topics like grouping, looking around, and performance. You will explore how to leverage Regular Expressions in Python, some advanced aspects of Regular Expressions and also how to measure and improve their performance. You will get a better understanding of the working of alternators and quantifiers. Also, you will comprehend the importance of grouping before finally moving on to performance optimization techniques like the RegexBuddy Tool and Backtracking. Mastering Python Regular Expressions provides all the information essential for a better understanding of Regular Expressions in Python.
Table of Contents (12 chapters)

Summary


This was a long chapter! We've covered a lot of material in it. We began with how strings work in Python and their different notations in Python 2.x and Python 3.x. After that, we looked at how to build regular expressions, the objects and interface the re module give us to deal with them, and the most important operations for searching and modifying strings. We also learned how to extract information from a pattern through MatchObject, such as the position or the groups of a match. We also learned how to modify the default behavior of some character classes and metacharacters using the compilation flags. And finally, we've seen how to deal with Unicode and the new features we can find in Python 3.x.

Throughout this chapter, we've seen that groups are crucial part of regular expressions and that many operations of the re module are meant to be used with groups. That's why we cover groups in depth in the following chapter.