JS高程学习笔记：ECMAScript引用类型之Array类型…

var num = new Array();//创建一个空的数组
var num = new Array(20);//创建一个length值为20的数组
var num = new Array("1","2","3");//创建一个包含三个字符的数组

var num = new Array(3); //创建一个包含3个项的数组，可省略new
var num1 = new Array("yellwo");//创建包含一项的数组，可省略new

var num = ["1", "2", "3"];//["1", "2", "3"]
var num1 = [];//[]
var num2 = [1,2,];//[1,2,undefined]
var num3 = [,,];//[undefined,undefined,undefined]
console.log(num);

var num = ['1', '2', '3'];//定义一个字符串数组
console.log(num[0]);//索引第一项
num[2] = "4";//修改数组中的第三项
num[3] = "5";//新值第五项
console.log(num);

var str = ["one", "two", "three"];
var num = [];

console.log(str.length);//3
console.log(num.length);//0

var str = ["one", "two", "three"];//创建包含3个字符串的数组
str.length = 2;
console.log(str[2]);//undefined

var str = ["one", "two", "three"];//创建包含3个字符串的数组
str.length = 4;
console.log(str[3]);//undefined

var str = ["one", "two", "three"];//创建包含3个字符串的数组
str[str,length] = "four";//添加到第四个项
str[str.length] = "five";//添加到第五个项

var str = ["one", "two", "three"];//创建包含3个字符串的数组
str[99] = "Ninety-nine";
console.log(str.length);//100

var arr = [];
console.log(arr instanceof Array);//true

var arr = [];
console.log(Array.isArray(arr));//true

var str = ["one", "two", "three"];
console.log(str.toString());//one,two,three 返回字符串
console.log(str.valueOf());//["one", "two", "three"] 返回数组
console.log(str);//["one", "two", "three"] 返回数组

var person1 = {
toLocaleString : function () {
return "1";
},
toString : function() {
return "2";
}
};
var person2 = {
toLocaleString : function () {
return "1";
},
toString : function() {
return "2";
}
};
var people = [person1, person2];
console.log(people); //
console.log(people.toString()); //
console.log(people.toLocaleString()); //

var arr = ["1", "2", "3"];
console.log(arr.join(","));//1,2,3
console.log(arr.join("||"));//1||2||3