How to use js regular expressions

This article mainly introduces how to use js regular expressions related knowledge, detailed and easy to understand, simple and fast operation, with a certain reference value, I believe that everyone will have a harvest after reading this article how to use js regular expressions, let's take a look at it.

1. defined

Regular expressions are used to match text according to a "given pattern." Often used to match text such as Email addresses.

There are two ways to create regular expressions:

var regex = /xyz/i;var regex = new RegExp('xyz',i);

The above two ways are equivalent, each creating a new regular expression object. The former is recommended because it is efficient, convenient and intuitive.

2. creation method

There are two ways: constructor and literal

(1) Constructors

var reg=new RegExp(']+%>','g');

(2) literal

var reg=/]%>/g;

g: global, full-text search, default search to the first result and then stop

i: ingore case, ignore case, default case sensitive

m: multiple lines, multiline search (change the meaning of ^and $so that they match the beginning and end of any line, respectively, rather than just the beginning and end of the entire string)

3. usage

exec: RegExp method that performs a search for a match in a string and returns an array (null if no match)

test: RegExp method that tests for a match in a string and returns true or false

match: Executes the String method that finds a match in a string, returning an array and null if there is no match

matchAll: Executes the String method to find all matches in a string, which returns an iterator

search: Tests for a matching String method in a string and returns the index of the location of the match, or-1 on failure

replace: Executes the String method to find a match in a string and replaces the matched substring with a replacement string

split: String method that separates a string using a regular expression or a fixed string and stores the separated substring in an array

For example:

Use the exec method to find a match in a string:

const myRe = /d(b+)d/g;const myArray = myRe.exec("cdbbdbsbz"); About "js regular expression how to use" The content of this article is introduced here, thank you for reading! I believe everyone has a certain understanding of "how to use js regular expressions" knowledge. If you still want to learn more knowledge, please pay attention to the industry information channel.