JS經常使用數組方法及實例

1.join(separator):將數組的元素組起一個字符串,以separator爲分隔符數組

var a = [1,2,3,4,5];
var b = a.join("|"); //若是不用分隔符,默認逗號隔開。
document.write(a); //1,2,3,4,5
document.write('<br/>');
document.write(b);//1,2,3,4,5

2.pop:刪除原數組最後一項,並返回刪除元素的值;若是數組爲空則返回undefined spa

var a = [1,2,3,4,5];
var b = a.pop(); 
document.write(a);//1,2,3,4
document.write('<br/>');
document.write(b);//5

3.push:將參數添加到原數組末尾,並返回數組的長度code

var a = [1,2,3,4,5];   
var b = a.push(6,7); 
document.write(a);//1,2,3,4,5,6,7
document.write('<br/>');
document.write(b);//7

4.shift:刪除數組開頭項 返回被刪除的開頭項目;若是數組爲空則返回undefinedblog

var a = [1,2,3,4,5];   
var b = a.shift(); 
document.write(a);//1,2,3,4
document.write('<br/>');
document.write(b); //5

5.unshift:將參數添加到原數組開頭,並返回數組的長度排序

var a = [1,2,3,4,5];   
var b = a.unshift(-2,-1); 
document.write(a);//-2,-1,1,2,3,4,5
document.write('<br/>');
document.write(b);//7

6.sort(orderfunction):按指定的參數對數組進行排序字符串

var a = [9,1,7,3,5,4,6,2];   
var b = a.sort();
document.write(a);//1,2,3,4,5,6,7,9
document.write('<br/>');
document.write(b);//1,2,3,4,5,6,7,9

7.reverse:將數組反序it

var a = [1,2,3,4,5];   
var b = a.reverse(); 
document.write(a);//5,4,3,2,1,
document.write('<br/>');
document.write(b);//5,4,3,2,1,

8.concat:返回一個新數組,是將參數添加到原數組中構成的io

var a = [1,2,3,4,5];   
var b = a.concat(6,7); 
document.write(a);//1,2,3,4,5
document.write('<br/>');
document.write(b);//1,2,3,4,5,6,7

9.slice(start,end):返回從原數組中指定開始下標到結束下標之間的項組成的新數組function

var a = [1,2,3,4,5,6];   
var b = a.slice(2,5); 
document.write(a);//1,2,3,4,5,6
document.write('<br/>');
document.write(b);//3,4,5

10.splice(start,deleteCount,val1,val2,...):10.從start位置開始刪除deleteCount項,並從該位置起插入val1,val2,...class

var a = [1,2,3,4,5,6,7,9];   
var b = a.splice(2,3,1,8,9);
document.write(a);//1,2,1,8,9,6,7,9
document.write('<br/>');
document.write(b);//3,4,5

11.toString()將數組轉換爲一個字符串,而且返回這個字符串

var a= [1,2];
document.write(a.toString());//1,2
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