bite_size_js.tar.gz

RunNode12

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

## Benefit of strings with RegExp objects 

What is the point of having an entire object dedicated to defining and using a regular expression when the literal notation alternative exists? Is this another one of those crazy quirks from JavaScript? 

Actually, no, it isn’t, and we’ll explain why. The literal notation for regular expressions works great, and it is usually the one we prefer when it comes to using them. You’re probably thinking:  *Then why the heck did they add an alternative to what is already perfect?* That is a very fine question!


Both alternatives are capable of doing exactly the same. The only benefit that the object version has over its literal counterpart comes from somewhere else: *strings*.

You see, the `RegExp` object takes its arguments as strings. And what can you do with strings? You’re correct: you can concatenate them and use ES6’s templating mechanics!
And that is why this object was added to the language: because it provides developers with the ability to write dynamic expressions.  In other words, you can create the RegExp during run-time using, for example, user input.

## Exercise: modifying the CSS of a webpage  

So, for our second exercise, let’s try to create a function that will grab the user’s selected color and modify a page CSS to replace all instances of that color for the color *white.*
Here is the simple CSS for our page:







# Benefit of strings with RegExp objects 

What is the point of having an entire object dedicated to defining and using a regular expression when the literal notation alternative exists? Is this another one of those crazy quirks from JavaScript? 

Actually, no, it isn’t, and we’ll explain why. The literal notation for regular expressions works great, and it is usually the one we prefer when it comes to using them. You’re probably thinking:  *Then why the heck did they add an alternative to what is already perfect?* That is a very fine question!


Both alternatives are capable of doing exactly the same. The only benefit that the object version has over its literal counterpart comes from somewhere else: *strings*.

You see, the `RegExp` object takes its arguments as strings. And what can you do with strings? You’re correct: you can concatenate them and use ES6’s templating mechanics!
And that is why this object was added to the language: because it provides developers with the ability to write dynamic expressions.  In other words, you can create the RegExp during run-time using, for example, user input.

# Exercise: modifying the CSS of a webpage  

So, for our second exercise, let’s try to create a function that will grab the user’s selected color and modify a page CSS to replace all instances of that color for the color *white.*
Here is the simple CSS for our page:







Challenge yourself with an example that uses the RegExp object to create dynamic regular expressions to solve the problem provided in 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

Dynamic Regular Expressions

Benefit of strings with RegExp objects

Exercise: modifying the CSS of a webpage