What are the uses of Array objects in JavaScript?-JS Tutorial-php.cn

What are the uses of Array objects in JavaScript?

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Release： 2018-12-14 16:34:14

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We have already introduced the usage of the properties and methods of the What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript? object in the previous article How to use the What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript? object in JavaScript, follow In this article, we will take a look at other uses of What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript? objects.

What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?

Let’s take a look at an example first

The code is as follows

<!DOCTYPE html>
<html>
  <head>
   <meta charset="utf-8">
    <title>JavaScript</title>
  </head>
  <body>
    <script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      console.log(family);
    </script>
  </body>
</html>

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Let’s introduce it based on this example Some usages of What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript? objects

Delete elements at the end of the array

The code is as follows

<script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      var last = family.pop();
      console.log(family);
    </script>

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The running results are as follows

What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?

Add elements to the beginning of the array

The code is as follows

<script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      var newLength = family.unshift("Zero");
      console.log(family);
    </script>

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The running result is as follows

What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?

Get the subscript of the element

The code is as follows

<script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      var ban = family.indexOf("Soucy");
      console.log(ban);
    </script>

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The running result is as follows

What are the uses of Array objects in JavaScript?

From the above results, we can know that the subscript value of Soucy is 2.

Determine the subscript position and delete the element

The code is as follows

<script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      var removedFamily = family.splice(0,1);
      console.log(family);
    </script>

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The running effect is as follows

What are the uses of Array objects in JavaScript?

Copy an array

The code is as follows

  <script>
      var family= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      var FamilyCopied= new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?("Tom", "Jerry", "Soucy");
      console.log(FamilyCopied);
    </script>

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The running effect is as follows

What are the uses of Array objects in JavaScript?

Define an empty array

The empty array is used to define an array that does not contain any content.

The code is as follows

//定义一个空数组
var family = new What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?();
msgWhat are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?[0] = "Tom";
msgWhat are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript?[99] = "100Tom";
if (family.length==100) {
 console.log("数组的长度为100");
}

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Delete any part of the What are the uses of What are the uses of What are the uses of Array objects in JavaScript? objects in JavaScript? objects in JavaScript? object

var array=["A","B","C","D","E","F"]
delete array[1];
delete array[5];
console.log(array)

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The running effect is as follows

What are the uses of Array objects in JavaScript?

Note: Although two elements are deleted here, the length of the array remains unchanged. When splice deletes elements, the length of the array will change accordingly, and the subscript of the array will also change accordingly.

Creation of multidimensional arrays

A multidimensional array is an array that combines two or more types of elements.

JavaScript does not provide a method for multi-dimensional arrays, but you can implement multi-dimensional arrays by creating an array within an array.

Let’s look at the image below

One-dimensional array

What are the uses of Array objects in JavaScript?

Two-dimensional array

What are the uses of Array objects in JavaScript?

Let’s look at a specific example

var array = [
  [1,2,3],
  [4,5,6],
  [7,8,9]
];
var array1 = array[2];

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In the variable named array1, the value contained in the second element in the array array will be assigned [7,8,9]

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