


Introduction to JS functions for deleting array elements_javascript skills
split code to convert a string into an array and output it:
js delete array elements:
1.delete method: delete arr[1]
In this way, the length of the array remains unchanged. At this time, arr[1] becomes undefined, but it also has the advantage that the index of the original array remains unchanged. At this time, you can use
Copy code
This traversal method skips undefined elements
* This method will be supported by IE4.o from now on
2. Array object splice method: arr.splice(1,1);In this way, the array length changes accordingly, but the original array index also changes accordingly
The first 1 in the splice parameter is the starting index of deletion (counted from 0), here it is the second element of the array The second 1 is the number of elements to delete, here only one element is deleted , that is, 'b';
At this time, you can traverse the array elements in the normal way of traversing the array, such as for, because the deleted elements are not retained in the array
* This method is only supported after IE5.5
It is worth mentioning that while the splice method deletes array elements, it can also add new array elements
For example, arr.splice(1,1,'d','e'), d, e The elements are added to the array arr
JavaScript truncates an array by setting the length property of the array. The only way to shorten the length of an array is to use the delete operator to delete an element in the array. Although that element becomes undefined, the length property of the array does not There are two ways to delete elements and change the length of the array without changing.
/*
* Method: Array.remove(dx)
* Parameter: dx subscript of deleted element.
* Return: Modify on the original array Array */
//It is often used to reconstruct the array through traversal.
if(this[i]!=this[dx])
🎜>}
a = ['1','2','3','4','5'];
alert("elements: " a "nLength: " a.length);
a.remove(0); //Delete the element with subscript 0
alert("elements: " a "nLength: " a.length);
Copy code
The code is as follows:
/*
b = ['1','2','3','4','5'];
alert("elements : " b "nLength: " b.length);
b.baoremove(1); //Delete the element with index 1
alert("elements: " b "nLength: " b.length);
IE5 이하 버전에서는 JavaScript의 Array 객체가 배열 요소를 삭제하는 기성 메서드를 제공하지 않는다는 것을 알고 있습니다. IE5.5 버전에서는 splice 방식이 있기는 하지만 특정 항목(또는 여러 항목)을 삭제하지는 않고, 특정 항목(또는 여러 항목)의 값만 삭제하므로 해당 항목이 여전히 존재한다는 의미이다. 배열의 길이는 변경되지 않았습니다.
실제로 배열에 삭제 메소드를 직접 추가할 수 있습니다(실제로 배열 구성원에서 배열 항목을 제거하는 것을 의미합니다). 아마도 루프를 사용하여 배열을 재할당하는 것을 생각할 수도 있지만 이는 매우 비효율적입니다.
다음으로 Array 객체의 두 가지 방법인 Slice와 Concat을 사용하여 배열 삭제를 사용자 정의하는 방법을 소개합니다.
구체적인 코드는 다음과 같으니, 안에 있는 댓글을 주목해주세요.
Array.prototype.del=function(n ) { / /n은 0부터 시작하는 숫자를 나타냅니다.
//Prototype은 객체 프로토타입입니다. 여기에서 객체에 사용자 정의 메소드를 추가하는 방법을 참고하세요.
if(n 이것을 반환합니다.
else
return this.slice(0,n).concat(this.slice(n 1,this.length)); 두 개 이상의 배열로 구성된 새 배열입니다.
여기에 this.slice(0,n)/this.slice(n 1,this.length)를 반환하는 새로운 배열이 있습니다.
슬라이스 메서드: 시작 위치와 끝 위치를 각각 지정하는 두 개의 매개변수를 사용하여 배열의 세그먼트를 반환합니다.
*/
}
//이 방법을 직접 추가해 보겠습니다.
var test=new Array(0,1,2,3,4,5);
test =test .del(3); //0부터 계산하면 여기서 4번째 항목이 삭제됩니다.
alert(test);
이런 방식으로 요구 사항을 충족하기 위해 Array 객체의 두 가지 메서드만 사용합니다.

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



Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...

There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.

How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...

In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...

Explore the implementation of panel drag and drop adjustment function similar to VSCode in the front-end. In front-end development, how to implement VSCode similar to VSCode...

Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.
