search
HomeWeb Front-endJS TutorialSummary of common methods of js string() (graphic tutorial)

Summary of common methods of js string() (graphic tutorial)

May 18, 2018 pm 02:15 PM
javascriptstringSummarize

The following is a summary of common methods of js string() that I have compiled for you. Interested students can take a look.

Create a String object, syntax: new String(stringValue), this call will convert the parameter into a string and use it as a String object. In fact, any string constant is a String object, which can be used directly as an object. The difference between this and using new String() to create an object is: the return value of typeof is different, one is "string", the other is "object".
string.indexOf(searchString,position)----Starting from the position (optional) position, search for the position where the first searchSting appears in the string and return it. For example: "hello,jack".indexOf("hello") will return 0;
"abcabc".indexOf("a",1) will return 4; (counting from 0)
string.lastIndexOf (searchString, position)--------Starting from the position (optional) position, search for the position where the last searchString appears in the string and return it. For example: "abcabc".lastIndexOf("b") will return 4
string.charAt(pos)-------returns the character at position pos in the string. For example: "abc".charAt(1) returns "b"
stirng.charCodeAt(pos)------returns the character code at position pos in the string. For ASCII characters, this returns their ASCII code. For example: "abc".charCodeAt(0) returns 97, which represents the ASCII code of character "a".
string.slice(start,end)--------Returns the substring whose starting position is start and the ending position is end (excluding end) in the string
string.split(separator ,linmit)------Cut the string into multiple substrings using separator as the separator, and return them as an array. linmit (optional) indicates the maximum length of the array, and the excess part will be discarded. The separator delimiter is not included in any substring. If separator is an empty string, an array consisting of the character sequence in the string is returned. If the split method does not take any parameters, it returns an array containing only the string itself and only one element.
string.split(separator,linmit)-------For example: "a1,b1,c1".split(",") will return ["a1","b1","c1"];
"a,b,c".split(",",2) will return ["a","b"];
"a,b,c".split("") will return [ "a",",","b",",","c"];
"ab,c".split() will return ["ab,c"]
string.substr(start ,length)--------Returns the substring whose starting position is start and whose length is length in the string. For example: "abcdefg".substr(1,3) will return "bcd";
string.substring(start,end)------The starting position in the returned string is start and the end position is end ( substring including end). The only difference between this method and the slice method is that slice does not accept negative parameters.
Replace and match strings
(1)replace(searchValue,replaceValue) method
This method replaces the first searchValue subcharacter that appears in the string String is replaced with replaceValue and the new string is returned. The original string is not affected.

例如:var str1="aaaa";
var str2=str1.replace("a","b");
alert(str2);//输出"baaa"
alert(str1);//输出"aaaa"

As can be seen from the above code, only one instance can be replaced using the replace function. If you want to replace multiple instances, you need to use regular expressions. For example, str.replace(/a/g,"b") can replace "aaaa" with "bbbb".
(2) match(reExp) method
Search for all substrings matching the regExp regular expression from the string and return them as an array. Using the conversion rules from object type to Boolean type, you can also determine whether a string matches the regular expression represented by regExp.

例如:var strInput=prompt("请输入一个数字:",0);
while(!strInput.match(/\d+/)){
         strInput=prompt("请输入一个数字:",0);
}

(3)search(regExp) method
Search the first substring matching the regExp regular expression from the string and return its index position . For example: var str="aabcabcabc";

alert(str.search(/abc/g));//显示“1”

(4)String 对象的大小写转换

var str="abc";
str.toLowerCase()//转化小写
str.toUpperCase()//转化大写

(5)String 对象的连接

var str="abc";
var str2=str.concact("def","ghi");
alert(str2);//将输出"abcdefghi"

上面是我整理给大家的js string()常用方法总结,希望今后会对大家有帮助。

相关文章:

在vue项目中使用sass的配置方法_vue.js

动态操作js/css文件有哪些方法

nodejs连接mysql数据库步骤详解

The above is the detailed content of Summary of common methods of js string() (graphic tutorial). For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
From Websites to Apps: The Diverse Applications of JavaScriptFrom Websites to Apps: The Diverse Applications of JavaScriptApr 22, 2025 am 12:02 AM

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python vs. JavaScript: Use Cases and Applications ComparedPython vs. JavaScript: Use Cases and Applications ComparedApr 21, 2025 am 12:01 AM

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

The Role of C/C   in JavaScript Interpreters and CompilersThe Role of C/C in JavaScript Interpreters and CompilersApr 20, 2025 am 12:01 AM

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

JavaScript in Action: Real-World Examples and ProjectsJavaScript in Action: Real-World Examples and ProjectsApr 19, 2025 am 12:13 AM

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

JavaScript and the Web: Core Functionality and Use CasesJavaScript and the Web: Core Functionality and Use CasesApr 18, 2025 am 12:19 AM

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding the JavaScript Engine: Implementation DetailsUnderstanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AM

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python vs. JavaScript: The Learning Curve and Ease of UsePython vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python vs. JavaScript: Community, Libraries, and ResourcesPython vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools