4日6日--数组的其他使用方法
新建一个数组
1、修改数组元素的间隔符。
2、使用concat对数组进行拼接。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>数组的其它方法1</title>
<script type="text/javascript">
var arr=["mike","jerry","tom"];
var str=arr.join();
console.log(str);
str=arr.join("-");
console.log(str);
str=arr.join("");
console.log(str);
//新建另一个数组
var arr2=["lisi","wang","zhang"];
//arr与arr2与"aa","bb",组成新的数组
var allName=arr.concat(arr2,["aa","bb"]);
console.log(allName);
console.log(arr);
</script>
</head>
<body>
</body>
</html>
使用shift，unshift，slice修改数组中的元素
1、shift取数组中的第0位元素
2、unshift 添加元素至数组的开头
3、slice(a,b) 从第a位开始，取b位元素组成的数组
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>数组的其它方法2</title>
<script type="text/javascript">
var arr=["mike","jerry","tom"];
var str=arr.shift();//相当于pop，只不过是在起始位置
console.log(str);//mike
console.log(arr);//[jerry,tom]
arr.unshift("andy","bob");
console.log(arr);//[andy,bob,jerry,tom]
console.log('=======');
arr.unshift("mike","john");//[mike,john,andy,bob,jerry,tom]
var subarr=arr.slice(3);
console.log(subarr);//[bob,jerry,tom]
subarr=arr.slice(1,3);
console.log(subarr);//[john,andy]
subarr=arr.slice(-3);
console.log(subarr);
</script>
</head>
<body>
</body>
</html>
使用splice 删除，插入，替换数组的元素
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>数组的其它方法3</title>
<script type="text/javascript">
var arr=["mike","john","andy","bob","jerry","tom"];
//删除:起始位置和删除数量
// arr.splice(0,1);//相当于shift
// arr.splice(arr.length-1,1);//相当于pop
// console.log(arr);
//["john","andy","bob","jerry"]
//插入：插入位置，0，插入数据
arr.splice(2,0,"lisi","zhang");
console.log(arr);
//["mike","john","lisi","zhang","andy","bob","jerry","tom"]
//替换：起始位置，被替换数量，新数据
// arr.splice(1,2,"lisi","zhang");
// console.log(arr);
// ["mike","john","lisi","zhang","jerry","tom"]
</script>
</head>
<body>
</body>
</html>
