If you can remember the first time you ever saw a programming language, you might have thought that it looked like complete gibberish.
However, the more you get to learn and understand a language, the more it starts to make sense.
You begin to know what you’re reading - just like when learning a foreign language.
But as with learning any language, there are easy things to grasp, and not so easy things.
There will be things that make sense straight away and things that will take years to master.
One of the notoriously difficult things to get your head around as a newbie coder (especially for me) is Regex.
Regex, short for regular expressions, is a sequence of characters that defines a search pattern.
It can be used to find, extract, or manipulate specific text within larger bodies of text. Regex uses special meta-characters and syntax rules to match text patterns, going beyond simple text matching.
Regex engines are built into most programming languages and tools to provide regex support.
At first glance Regex can seem daunting, it uses seemingly cryptic characters and rules, therefore it can be quite a challenge for beginners.
However, as a programmer, you’ll most likely encounter the use of Regex at some point so it’s worth getting comfortable with it.
There are many benefits to learning Regex that make it a valuable skill for any developer to have:
- Powerful text search/matching - Regex enables complex text search and string matching far beyond simple substring searches. You can match text based on intricate patterns.
- Search and replace - Using Regex capture groups, you can not only find text but also replace it with new values in one step. Great for find/replace tasks.
- Data extraction - Regex makes it easy to extract specific data from larger text sources like log files, APIs, or documents. This helps with data parsing and finding information.
- Input validation - Verifying input like user emails, phone numbers, or passwords is easy with Regex. You can validate that data is correctly formatted quickly.
- Faster than alternatives - Regex provides a fast and optimised way to work with text. Performance is excellent, better than iterating through strings manually.
Overall, knowing Regex will make you a more effective developer as it’s a versatile skill that can be applied in many scenarios.
Here are some common examples of how Regex is used:
- Email validation - Regex can check if a string matches the proper format for an email address. Helpful for validating user input.
- Log file parsing - Regex lets you extract only lines or fields you need from large log files, ignoring irrelevant data.
- Data scraping - When screen scraping or extracting data from sites, Regex can isolate the relevant data from HTML.
- Find and replace - Replace text matching a regex pattern across multiple files or a large dataset using powerful search/replace.
- Formatting checks - Check the proper formatting of things like phone numbers, postal codes, or product codes with a Regex match.
These are just a few examples. Regex has near-limitless use cases for working with text data.
With that in mind, there’s no better time to get started learning the patterns of Regex.
And fortunately, there are many great resources available where you can learn and practise Regex for free.
Let’s take a look at some of the top ones:
#1 - RegexOne
RegexOne is an interactive tutorial designed to teach the practical uses of Regular Expressions.
It begins with an introduction to the concept that everything in Regex is essentially a character forming part of a pattern or string.
The tutorial covers the use of common ASCII characters as well as Unicode characters for international text.
To advance to the next levels, you must apply the new syntax and concepts introduced in each lesson to match provided patterns, making the learning process engaging and efficient.
#2 - RegexLearn
RegexLearn is an online tutorial platform that provides step-by-step learning modules for mastering Regex.
Regardless of your level, the platform illustrates Regex usage across multiple programming languages and data analytics tools.
RegexLearn also includes a handy cheatsheet for quick referencing of Regex patterns and symbols, as well as a Playground feature to build, test, and share Regex patterns collaboratively, and a practice section to test and reinforce learning.
Furthermore, as an open-source project, RegexLearn encourages community contributions, creating an environment of collective growth and collaboration.
#3 - Codecademy
Codecademy's Learn the Basics of Regular Expressions course offers a deep dive into the practical uses of Regex.
The course highlights regex as a powerful and universal technique for finding patterns in strings, applicable across nearly all programming languages.
It goes through its usage in important tasks such as validating user input, performing search tasks, and testing code.
By learning the rules of regex through this course, you’ll gain the ability to apply regex proficiently in any language of your choosing.
#4 - Scrimba
This course, which incorporates freeCodeCamp's Regular Expressions curriculum, guides learners from the basic to advanced stages of regex, ensuring thorough understanding.
The standout feature of Scrimba's tutorial is its interactive nature. You can experiment with the expressions during the course, giving you a hands-on understanding of the details of regex.
This active engagement with code makes the knowledge more retainable compared to the passive viewing of typical video tutorials.
The Regular Expressions Tutorial on Regular-expressions.info is a great resource for learning and mastering regular expressions.
Starting from the basics, it's designed to be accessible for absolute beginners while also delving into advanced topics.
The tutorial provides insights into the inner workings of a regular expression engine, clarifying potential misconceptions and troubleshooting issues.
This understanding helps with crafting more complex regular expressions and eliminates the guesswork, making it a valuable tool for saving time and enhancing your proficiency in regex.
Unless you have the best memory in the world and regularly use Regex, you’re unlikely to remember all of the syntax and patterns (I know I never do!).
Therefore, it’s always handy to have a cheat sheet saved where you can quickly look up expressions whenever you need them.
Here are a few cheatsheets for regular expressions:
In conclusion, getting to grips with Regex can significantly enhance your data handling capabilities, such as validating user input, searching patterns in strings, or manipulating text data.
From the basics to the more advanced details, Regex is a powerful tool that, once understood, can be incredibly useful across various programming languages.
In this article, we explored different free resources, each with its unique learning approach. Whether you prefer interactive exercises, handy cheat sheets, hands-on practice, or detailed tutorials, there's a resource for you to start learning Regex.
Learning Regex, like any other programming concept, will require consistent practice and application.
So, no need to rush through the learning materials, take your time to understand and experiment with the patterns, and soon you'll find yourself handling text data like a pro.
Stay Regular, keep Expressing!
From your fellow ever-growing dev,
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