How to create an array object in js

This article will start a new chapter. Everything we want to perform cannot be separated from arrays. Today we will learn the simplest one, which is to create an array object. Only after it is created can it be used. Come and learn.

What we want to learn is arrays, so how can we not know what arrays are? Let’s first take a look at what an array is.

An array is an ordered sequence of elements. If you name a collection of a limited number of variables of the same type, this name is the array name. The variables that make up an array are called components of the array, also called elements of the array, and sometimes called subscript variables. The number used to distinguish the elements of an array is called a subscript. An array is a form in which multiple elements of the same type are organized in an ordered form for ease of programming. A collection of these homogeneous ordered data elements is called an array.

An array is a collection used to store multiple data of the same type.

After knowing these basic knowledge, let's look at how to create an array object.

var num = ['one', 'two'];
console.log(num.length);

Look at the results of this.

#As you can see, we have created two array objects. Let’s look at another example.

var nums = new Array("one","two","three");
console.log(nums.length);

The result is

In this way we have created three array objects, let's look at an example again.

var arr = new Array(3); 
arr[0] = "one";
arr[1] = "two";
arr[2] = "three";
console.log(arr.length);

The result is

We looked at three examples and used three methods to create array objects. Do you guys see the pattern?

Then let me talk about it.

方法一：
new Array();
方法二：
new Array(期望的数组元素个数);
方法三：
new Array(参数列表1,参数列表2, ..., 参数列表n);

Returns the newly created and initialized array. If the constructor array() is called without arguments, the returned array is empty and the length field is 0. When the constructor is called, passing it only a numeric argument, the constructor returns an array containing the specified number of elements and undefined elements.

When array() is called with other parameters, the constructor initializes the array with the value specified by the parameter. When a constructor is called as a function without the new operator, it behaves exactly as when called with the new operator.

[Recommended learning: javascript advanced tutorial]

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