This article summarizes some basic knowledge of JS arrays for everyone. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.
Array: Store a set of ordered data
The role of array: Store multiple items at once Data
How to define an array:
1. Constructor defines array: var array name=new Array();
2. Literal Define an array in a quantitative way: var array name=[];
[Related course recommendations: JavaScript video tutorial]
The meaning of the following arrays:
var 数组名=new Array(); // 空数组 var 数组名=new Array(值); // 数组定义了,有长度 var 数组名=new Array(值1,值2,值3....); // 定义数组并且有多个数据 var 数组名=[]; // 空数组 var 数组名=[值1,值2,值3]; // 有三个数据
Array elements: is the data stored in the array
Array length: is the number of elements in the array
Array index (subscript): Start from 0 and end with the length of the array minus 1
Set the element value of the array through the subscript: Array name [index] =value
Access the element value of the array through subscript:Array name[index]
The meaning of the following array:
var arr1=new Array();//空数组 var arr2=new Array(5);//长度为5的数组,每个数据的值是undefined var arr3=new Array(1,2,3,4,5);//长度为5分数组, var arr4=[];//空数组 var arr5=[1,2,3];//长度为3的数组 var arr6=["red","blue","green",1,true];//数组中元素的值的类型可以不一样 var arr7=[]; //设置数组的元素的值 arr7[0]=10; arr7[1]=20;
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