Zsolt Nagy - Regex Quick Syntax Reference: Understanding and Using Regular Expressions

Any source code or other supplementary material referenced by the author in this book is available to readers on GitHub via the books product page, located at www.apress.com/9781484238752 . For more detailed information, please visit www.apress.com/source-code .

About the Author

Zsolt Nagy

is a web development team lead, mentor, and software engineer living in Berlin, Germany. He programs with JavaScript, Perl, and other open source web technologies. Zsolt is also experienced in using and teaching regular expressions using these technologies. He writes a blog about lessons learned while solving complex problems, experimenting with technology, and teaching other people how to improve their skills. As a software engineer, he continuously challenges himself to stick to the highest possible standards.

You can read regular articles from me on

• zsoltnagy.eu , a blog on writing maintainable web applications

• devcareermastery.com , a career blog on designing a fulfilling career

Sign up to my e-mail list for regular free content. I am the author of these two books:

• ES6 in Practice: The Complete Developers Guide ( https://leanpub.com/es6-in-practice )

• The Developers Edge: How to Double Your Career Speed with Soft-Skills ( https://leanpub.com/thedevelopersedge )

Check them out if these topics are interesting to you.

About the Technical Reviewer

Massimo Nardone

has a master of science degree in computing science from the University of Salerno, Italy, and has more than 24 years of experience in the areas of security, web/mobile development, cloud, and IT architecture. His IT passions are security and Android.

Specifically, he has worked as a project manager, software engineer, research engineer, chief security architect, information security manager, PCI/SCADA auditor, and senior lead IT security/cloud/SCADA architect.

He has also worked as a visiting lecturer and supervisor for exercises at the Networking Laboratory of the Helsinki University of Technology (Aalto University), and he holds four international patents (in the PKI, SIP, SAML, and proxy areas).

He currently works as the chief information security officer (CISO) for Cargotec Oyj and is a member of the ISACA Finland Chapter board.

Massimo has reviewed more than 45 IT books for different publishing companies and is the coauthor of Pro JPA 2 in Java EE 8 (Apress, 2018), Beginning EJB in Java EE 8 (Apress, 2018), and Pro Android Games (Apress, 2015).

I still remember my doomed encounters with regular expressions back when I tried to learn them. In fact, I took pride in not using regular expressions. I always found a long workaround or a code snippet. I projected and blamed my own lack of expertise on the hard readability of regular expressions. This process continued until I was ready to face the truth: regular expressions are powerful, and they can save you a lot of time and headache.

Fast-forward a couple of years. People I worked with encountered the same problems. Some knew regular expressions, and others hated them. Among the haters of regular expressions, it was quite common that they actually liked the syntax and grammar of their first programming language. Some developers even took courses on formal languages. Therefore, I made it my priority to show everyone a path toward their disowned knowledge to master regular expressions.

In todays world, we have to deal with processing a lot of data. Accessing data is not the main problem. Filtering data is. Regular expressions provide you with one type of filter that you can use to extract relevant data from the big chunks of data available to you. For instance, suppose you have an XML file containing 4GB of data on movies. Regular expressions make it possible to query this XML text so that you can find all movies that were filmed in Budapest in 2016, for instance.

Regular expressions are a must-have for software developers.

In front-end development, we often validate input using regular expressions. Many small features are also easier with regular expressions, such as splitting strings, parsing input, and matching patterns.