A collection of common methods for intercepting strings in JS
Strings in js are a very long-used data type, both in our actual development and in daily practice, and we often encounter fewer suffixes or more suffixes in the js strings we need. A suffix, which requires manipulation of strings. Let’s take a look at how to intercept strings! How to cut off the redundant part of the string!
We can easily do it using functions. Let’s take a look at which functions can do it!
Function: split()
Function: Use a specified delimiter to split a string and store it in an array
Example:
var str = "jpg|bmp|gif|ico|png"; var arr = str.split("|");
arr is an array containing the character values "jpg", "bmp", "gif", "ico" and "png"
Function: Join()
Function: Combine an array into a string using the delimiter of your choice
Example:
var arry = new Array('jpg','bmp','gif','ico','png'); var str = arry.join('|'); //结果是jpg|bmp|gif|ico|png
Function: indexOf()
Function: Return the subscript of the first character matching the substring in the string
var myString = "JavaScript"; var w = myString.indexOf("v"); // w = 2 var x = myString.indexOf("s"); // x = 4 var y = myString.indexOf(”Script”); // y = 4 var z = myString.indexOf(”key”); // z = -1
Function: substring()
Function: String interception, for example, if you want to get "Minidx" from "MinidxSearchEngine", you need to use substring(0,6)
##Syntax stringObject.substring(start,stop)
Parameter descriptionstart Required. A nonnegative integer that specifies the position in stringObject of the first character of the substring to be extracted.
stop Optional. A nonnegative integer that is one position in the stringObject that is one more than the last character of the substring to be extracted. If this parameter is omitted, the returned substring will go to the end of the string.
Return valueA new string value contains a substring of stringObject, and its content is from start to stop-1 All characters whose length is stop minus start.
DescriptionThe substring returned by the substring method includes the characters at start, but does not include the characters at end.
If start and end are equal, then this method returns an empty string (that is, a string with a length of 0).
If start is greater than end, then this method will exchange the two parameters before extracting the substring.
If start or end is negative, then it will be replaced with 0.
Function: substr ()Definition and usage
The substr method is used to return a substring of the specified length starting from the specified position.
SyntaxstringObject.substr(start [, length])
Parameter descriptionstart Required. The starting position of the desired substring. The first character in the string has index 0.
length Optional. The number of characters that should be included in the returned substring.
DescriptionIf length is 0 or a negative number, an empty string will be returned.
If this parameter is not specified, the substring will continue to the end of stringObject
Detailed explanation of javaScript string tool class StringUtils
This article mainly introduces the javaScript string tool class StringUtils in detail .Detailed introduction to JavaScript strings
Strings in JavaScript are represented by characters enclosed in '' or "".The above is the detailed content of A collection of common methods for intercepting strings in JS. For more information, please follow other related articles on the PHP Chinese website!

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.

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 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 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 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.

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.


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

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

WebStorm Mac version
Useful JavaScript development tools

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.