Explore JavaScript regular expressions: learn about regex history, create patterns with special characters, parse data, and match passwords/emails, gaining comprehensive text processing skills.

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Regular Expressions, also known as Regex, come in handy in a multitude of text processing scenarios. Regex defines a search pattern using symbols and allows you to find matches within strings. The applications of this span from software engineering to data science and beyond.

In this course, you will begin with an introduction to regex, its history, and various types of regular expressions. 

You will then learn how to create your own regular expressions using various techniques and special characters. In the latter half of the course, you will explore RegExp Objects, how to parse data, turn phrases into an array of strings, and lastly password and email pattern matching.

By the end of this course, you will be a regular expressions expert.

JavaScript Regular Expressions in Detail

# Regular expression to match sections of the URL

Finally, we're looking for anything that comes after the first slash right after your hostname (i.e., after the *.com*). Again, we’re keeping it simple for now, so matching that should be quite simple.
For the breakdown:


```javascript
/\.com(\/[a-z\.]+)?/g
```
And for the breakdown:


- The mandatory *.com* at the start is clearly escaping the dot at the beginning.
- The optional condition for the URL is given by the last **?** after the capturing group.
- The only characters we’re allowing for the URL are anything between a to z and the actual dot, so you can add things like *index.html.* Yes, this is an oversimplification but it should be enough to understand the concept.

Now that we’ve individually matched all parts of the URL, let’s put them together and try to understand where the non-capturing groups come into play.

# Using non-capturing groups
Concatenating all three expressions together looks like this:

```javascript
/(https?|ftp):\/\/(www\.)?([a-z-]+)\.com(\/[a-z\.]+)?/g
```
Testing the full expression on regex101.com will allow you to see how all three testing strings match! One of the great features of this tool is that, on the right side of the screen, you can see the three different matches.





Let's continue our example of capturing the hostname of a URL. Additionally, you will also be familiarized with non-capturing groups at the end of this lesson.


The Beginning of Regular Expressions

The Anatomy of Regular Expressions

The RegExp Object

Thinking in Regular Expressions

Regular Expressions in the Wild

Wrapping Up

Special Characters: Matching the URL and Non-Capturing Groups

Regular expression to match sections of the URL