js常用数组操作方法简明总结_基础知识

//javascript 中的数组分割
var colors = ["red","green","blue"];
//alert(colors.toString());
alert(colors.join("|")); //返回结果是red|green|blue
var colors = ["red","green","blue",null];
alert(colors.join("|"));//red|green|blue|
//注意当数组里面有值是null或者是undefined的时候 返回的结果是以空的字符串表示的
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//数组删除和添加
var colors = ["red","green","blue"];
//alert(colors.toString());
colors.push("white","test");//返回的结果是数组的长度
alert(colors.join("|"));//结果是red|green|blue|white|test
//往数组的开头添加元素
var colors = ["red","green","blue","test"];
var item = colors.unshift("first");//数组的开头添加一个元素
alert(colors.join("|"));//返回最后的数组


//删除元素
var colors = ["red","green","blue","test"];
var item = colors.pop();//返回删除的选项结果test
alert(colors.join("|"));//返回最后的数组结果red|green|blue
//删除开头元素
var colors = ["red","green","blue","test"];
var item = colors.shift();//删除数组的第一个选项
alert(colors.join("|"));//返回最后的数组
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//数组顺序事例
//顺序颠倒
var colors = ["red","green","blue","test"];
colors.reverse();
alert(colors);//结果是：test,blue,green,red
//数组排序
var values = [0,1,5,10,7];
values.sort(compare);
alert(values);
//document.writeln(values);

}
 function compare(value1,value2){
	if(value1value2){
		return -1 ;
	}else return 0 ;
} 
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//向数组中添加数组 concat()方法
var colors = ["color","red"];
var colors2 = colors.concat(["ccc","bbbb"],'3333',['vvccxx',['oolll','lll']]);
alert(colors2);//返回结果是：color,red,ccc,bbbb,3333,vvccxx,oolll,lll

//slice()方法复制数组中的元素并不会破坏之前的元素
var colors = ["color","red",'eeee','221111'];
var colors2 = colors.slice(1);//从1开始进行复制
alert(colors2);//结果是：red,eeee,221111

var colors = ["color","red",'eeee','221111'];
var colors2 = colors.slice(1,3);//从1开始进行复制到第3个位置结束
alert(colors2);//结果是red,eeee
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//数组中删除元素
var a = [1,2,3,5,8];
var r = a.splice(0,2); //删除前2项
alert(a);//结果是3,5,8

var a = [1,2,3,5,8];
var r = a.splice(1,1,100,200); //从第2个数开始删除一项 然后插入100 200
alert(a);//结果是1,100,200,3,5,8