![]() Up until now, we’ve created simple regular expression patterns. Special Characters to Know for JavaScript Regular Expressions (Regex) ![]() This is the most basic pattern, which simply matches the literal text with the test string. We are going to use the test() method in this article. input: -> Is the actual string passed. index: -> Is where the regular expression starts. It accepts a string that we have to test against a regular expression. This method returns an array containing all the matched groups. It accepts a string which we have to test against a regular expression, and it returns true or false depending upon if the match is found or not. This method is used to test whether a match has been found or not. There are two main methods for testing regular expressions. JavaScript Regular Expression (Regex) Methods Since forward slashes are used to enclose patterns in the above example, you have to escape the forward slash ( / ) with a backslash ( \ ) if you want to use it as a part of the regex. Both regex objects will have the same methods and properties attached to them. No matter which method you choose, the result is going to be a regex object. So, you have to use a regular expression constructor. There might also be cases where you want to create regular expressions dynamically, in which case, regex literal won’t work. I will explain these later in this article. Syntax: /pattern/flags Regex Literal Example var regexLiteral = /abc/ Syntax: new RegExp(pattern) Example var regexConst = new RegExp('abc') It can either be created with a RegExp constructor, or by using forward slashes ( / ) to enclose the pattern. There are two ways to create a regular expression in JavaScript. How to Create a Regular Expression in JavaScript More on JavaScript: 5 Ways to Check Data Types in JavaScript Using Typeof Regular expressions allow you to check a string of characters like an e-mail address or password for patterns to see if they match the pattern defined by that regular expression and produce actionable information. They form a small language of their own, which is a part of many programming languages like JavaScript, Perl, Python, PHP and Java. Regular expressions are a way to describe patterns in a string of data. In order to fully understand the regex world, you first need to learn the basic concepts on which you can later build. The truth is, properly understanding regular expressions will make you a much more effective programmer. They’re an important part of programming languages like JavaScript, Python, Php and Java, among others. ![]() Regular expressions (Regex) are a way of describing patterns in a string of data, which allows you to search for data strings, like email addresses or passwords, that match that pattern.
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