Introduction to common operation methods of js array

Arrays and operation methods

An array is a collection of data. In JavaScript, the data in the array can be of different types.

Methods to define arrays

//对象的实例创建
var aList = new Array(1,2,3);
//直接量创建
var aList2 = [1,2,3,'asd'];

Methods to operate data in arrays

1. Get the length of the array: aList.length;

var aList = [1,2,3,4];
alert(aList.length); // 弹出4

2. Use Subscript operates on a certain data in the array: aList[0];

var aList = [1,2,3,4];
alert(aList[0]); // 弹出1

3. join() merges the array members into a string through a separator

var aList = [1,2,3,4];
alert(aList.join('-')); // 弹出 1-2-3-4

4. push() and pop() adds or deletes members from the end of the array

var aList = [1,2,3,4];
aList.push(5);
alert(aList); //弹出1,2,3,4,5
aList.pop();
alert(aList); // 弹出1,2,3,4

5, unshift() and shift() adds or deletes members from the front of the array

var aList = [1,2,3,4];
aList.unshift(5);
alert(aList); //弹出5,1,2,3,4
aList.shift();
alert(aList); // 弹出1,2,3,4

6, reverse() reverses the array Turn

var aList = [1,2,3,4];
aList.reverse();
alert(aList); // 弹出4,3,2,1

7. indexOf() returns the index value of the first occurrence of the element in the array

var aList = [1,2,3,4,1,3,4];
alert(aList.indexOf(1));

8. splice() adds or deletes members from the array

var aList = [1,2,3,4];
aList.splice(2,1,7,8,9); //从第2个元素开始，删除1个元素，然后在此位置增加'7,8,9'三个元素
alert(aList); //弹出 1,2,7,8,9,4

Multidimensional array

Multidimensional array refers to an array whose members are also arrays.

var aList = [[1,2,3],['a','b','c']];
 
alert(aList[0][1]); //弹出2;

Recommended tutorial: js introductory tutorial

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