JavaScript Enhancement Tutorial - RegExp Object
This article is the official HTML5 training tutorial of H5EDU organization. It mainly introduces: JavaScript enhancement tutorial—RegExp object
The RegExp object is used to specify the content to be retrieved in the text.
What is RegExp?
RegExp is the abbreviation of regular expression.
When you retrieve a certain text, you can use a pattern to describe what you want to retrieve. RegExp is this pattern.
Simple pattern can be a single character.
More complex patterns include more characters and can be used for parsing, format checking, replacement, etc.
You can specify the search position in the string, the type of characters to be searched, etc.
Define RegExp
RegExp object is used to store retrieval patterns.
Use the new keyword to define the RegExp object. The following code defines a RegExp object named patt1 whose pattern is "e": var patt1=new RegExp("e");When you use this RegExp object to search within a string, you are looking for the character "e" ".
Methods of RegExp object
RegExp object has 3 methods: test(), exec() and compile().
test()
test() method retrieves a specified value in a string. The return value is true or false.
Example: var patt1=new RegExp("e"); document.write(patt1.test("The best things in life are free")); Since the letter "e" exists in the string, the output of the above code Will be: true
exec()
exec() method retrieves the specified value in the string. The return value is the found value. If no match is found, null is returned.
Example 1: var patt1=new RegExp("e"); document.write(patt1.exec("The best things in life are free")); Since the letter "e" exists in the string, the above code The output will be: e
Example 2:
You can add a second parameter to the RegExp object to set the retrieval. For example, if you need to find all occurrences of a certain character, you can use the "g" parameter ("global").
For complete information on how to modify the search pattern, please visit our RegExp Object Reference Manual.
When using the "g" parameter, exec() works as follows:
Find the first "e" and store its position
If you run exec() again, start retrieval from the stored position and find Next "e" and store its position var patt1=new RegExp("e","g"); do { result=patt1.exec("The best things in life are free"); document.write(result) ; } while (result!=null) Due to the 6 "e" letters in this string, the output of the code will be: eeeeeenull
compile()
compile() method is used to change RegExp.
compile() can not only change the retrieval mode, but also add or remove the second parameter.
Example: var patt1=new RegExp("e"); document.write(patt1.test("The best things in life are free")); patt1.compile("d"); document.write(patt1. test("The best things in life are free")); Since "e" exists in the string but not "d", the output of the above code is: truefalse

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

PHP regular expression verification: Number format detection When writing PHP programs, it is often necessary to verify the data entered by the user. One of the common verifications is to check whether the data conforms to the specified number format. In PHP, you can use regular expressions to achieve this kind of validation. This article will introduce how to use PHP regular expressions to verify number formats and provide specific code examples. First, let’s look at common number format validation requirements: Integers: only contain numbers 0-9, can start with a plus or minus sign, and do not contain decimal points. floating point

To validate email addresses in Golang using regular expressions, follow these steps: Use regexp.MustCompile to create a regular expression pattern that matches valid email address formats. Use the MatchString function to check whether a string matches a pattern. This pattern covers most valid email address formats, including: Local usernames can contain letters, numbers, and special characters: !.#$%&'*+/=?^_{|}~-`Domain names must contain at least One letter, followed by letters, numbers, or hyphens. The top-level domain (TLD) cannot be longer than 63 characters.

In Go, you can use regular expressions to match timestamps: compile a regular expression string, such as the one used to match ISO8601 timestamps: ^\d{4}-\d{2}-\d{2}T \d{2}:\d{2}:\d{2}(\.\d+)?(Z|[+-][0-9]{2}:[0-9]{2})$ . Use the regexp.MatchString function to check if a string matches a regular expression.

As a modern programming language, Go language provides powerful regular expressions and string processing functions, allowing developers to process string data more efficiently. It is very important for developers to master regular expressions and string processing in Go language. This article will introduce in detail the basic concepts and usage of regular expressions in Go language, and how to use Go language to process strings. 1. Regular expressions Regular expressions are a tool used to describe string patterns. They can easily implement operations such as string matching, search, and replacement.

PHP Regular Expressions: Exact Matching and Exclusion Fuzzy inclusion regular expressions are a powerful text matching tool that can help programmers perform efficient search, replacement and filtering when processing text. In PHP, regular expressions are also widely used in string processing and data matching. This article will focus on how to perform exact matching and exclude fuzzy inclusion operations in PHP, and will illustrate it with specific code examples. Exact match Exact match means matching only strings that meet the exact condition, not any variations or extra words.

The method of using regular expressions to verify passwords in Go is as follows: Define a regular expression pattern that meets the minimum password requirements: at least 8 characters, including lowercase letters, uppercase letters, numbers, and special characters. Compile regular expression patterns using the MustCompile function from the regexp package. Use the MatchString method to test whether the input string matches a regular expression pattern.

PHP is a widely used programming language, especially popular in the field of web development. In the process of web development, we often encounter the need to filter and verify text input by users, among which character filtering is a very important operation. This article will introduce how to use regular expressions in PHP to implement Chinese character filtering, and give specific code examples. First of all, we need to clarify that the Unicode range of Chinese characters is from u4e00 to u9fa5, that is, all Chinese characters are in this range.

Regular expression wildcards include ".", "*", "+", "?", "^", "$", "[]", "[^]", "[a-z]", "[A-Z] ","[0-9]","\d","\D","\w","\W","\s&quo
