Declare Arrays in jQuery

Simple code snippet declaring JavaScript arrays. Like other JavaScript variables, you don't need to declare them before using an array. I love declaring them so I can read easily what is going on, which is a good habit! Example 1 – Array Constructor

// 使用数组构造函数声明数组
var arlene1 = new Array();
var arlene2 = new Array("First element", "Second", "Last");

Example 2 - Literal Notation

// 使用字面量表示法声明数组
var arlene1 = [];
var arlene2 = ["First element", "Second", "Last"];

Example 3 - Implicit Declaration

// 从方法的返回值创建数组
var carter = "I-learn-JavaScript";
var arlene3 = carter.split("-");

To avoid script errors, you should develop the habit of initializing arrays when declaring them, as follows:

// 使用字面量表示法声明空数组：
var arlene = [];
// 变量现在包含长度为零的数组

After checking my code on jslint.com, I found that it means that using an array constructor declares an array is considered a bad practice! It recommends using literal notation. FAQs for declaring and initializing arrays in jQuery and JavaScript

What is the basic syntax for declaring arrays in jQuery?

In jQuery, arrays are declared in similar ways to JavaScript. The basic syntax for declaring an array in jQuery is as follows:

var arrayName = [];

In this syntax, "arrayName" is the name of the array. Square brackets indicate empty arrays. You can also initialize the array with values ​​when declaring, as shown below:

var arrayName = [value1, value2, value3];

In this syntax, "value1", "value2", and "value3" are the initial values ​​of the array.

How to add elements to jQuery array?

You can use the push() method to add elements to the jQuery array. Here is an example:

var arrayName = []; arrayName.push(value);

In this example, "value" is the value to be added to the array. The push() method adds the value to the end of the array.

How to delete elements from jQuery array?

You can use the splice() method to delete elements from the jQuery array. Here is an example:

var arrayName = [value1, value2, value3]; arrayName.splice(index, 1);

In this example, "index" is the index of the element to be deleted. The second parameter of the splice() method is the number of elements to be deleted.

How to access elements in jQuery array?

You can use its index to access elements in a jQuery array. Here is an example:

var arrayName = [value1, value2, value3]; var value = arrayName[index];

In this example, "index" is the index of the element to be accessed. The array index starts at 0, so the first element of the array is located at index 0.

How to find the length of a jQuery array?

You can use the length property to find the length of the jQuery array. Here is an example:

var arrayName = [value1, value2, value3]; var length = arrayName.length;

In this example, the length attribute returns the number of elements in the array.

How to iterate through jQuery arrays?

You can iterate through the jQuery array using the for loop or jQuery each() function. Here is an example of using the for loop:

// 使用数组构造函数声明数组
var arlene1 = new Array();
var arlene2 = new Array("First element", "Second", "Last");

In this example, for loops over each element in the array and records it to the console.

How to sort jQuery arrays?

You can use the sort() method to sort jQuery arrays. Here is an example:

var arrayName = [value3, value1, value2]; arrayName.sort();

In this example, the sort() method sorts the elements of the array in ascending order.

How to reverse jQuery array?

You can reverse the jQuery array using the reverse() method. Here is an example:

var arrayName = [value1, value2, value3]; arrayName.reverse();

In this example, the reverse() method inverts the order of elements in the array.

How to concatenate elements of jQuery array into strings?

You can use the join() method to concatenate elements of the jQuery array into a string. Here is an example:

var arrayName = [value1, value2, value3]; var string = arrayName.join(separator);

In this example, "separator" is the string used between each element in the result string.

How to check if there is a value in the jQuery array?

You can use the indexOf() method to check whether there are values ​​in the jQuery array. Here is an example:

var arrayName = [value1, value2, value3]; var index = arrayName.indexOf(value);

In this example, "value" is the value to be checked. The indexOf() method returns the index in which the value first appears in the array, and if the value is not found, it returns -1.

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