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Basic JavaScript Regular Expression Example

By Sam Deering

JavaScript

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I have jotted down a quick post on a Basic JavaScript Regular Expression Example to give beginners out there a taste of the power of using Regex in jQuery/JavaScript.

Example: Want to extract the price, could be an integer or float from a dataset of prices.

Dataset:

$55.99
$55
$55.00
etc...

Regex pattern:

/[(0-9)+.?(0-9)*]+

You can use a Regular Expression tool such as the Firefox Add-on: Regular Expressions Tester.

regular-expressions-price-1

As you can see in tool, the matched expression is highlighted yellow.

var price = '$55.99';
var priceRegex = /[(0-9)+.?(0-9)*]+/igm;

console.log(priceRegex.test(price));
console.log(price.match(priceRegex));
console.dir(priceRegex.exec(price));

Now if we perform some basic JS tests using .test(), match() and exec() this is what we get.

regular-expressions-price-2

The exec() function result at index 0 gives us our match so the full code for extracting the price.

var price = '$55.99';
var priceRegex = /[(0-9)+.?(0-9)*]+/igm;

var price = parseFloat(priceRegex.exec(price));
console.log(price);
//output: 55.99

This is only a very basic example, but should give you a taste of how to use Regex in JavaScript. Comments welcomed.

Sam Deering has 15+ years of programming and website development experience. He was a website consultant at Console, ABC News, Flight Centre, Sapient Nitro, and the QLD Government and runs a tech blog with over 1 million views per month. Currently, Sam is the Founder of Crypto News, Australia.

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