//1. 使用Array构造函数
var colors = new Array();//2.如果预先知道数组要保存的项目数量，也可以给构造函数传递该数量，改数量会自动变成length的属性值
var colors2 = new Array(20);
alert(colors2.length);    //20//3.也可以向Array构造函数传递数组中应该包含的项。
var colors3 = new Array("red", "blue", "green");//4.给构造函数传递一个值时，如果传递的是数值，表示该数组的长度。如果传递的是其他类型，则会创建包含那个值的数组
var colors4 = new Array(3);    // 创建一个包含3项的数组
var colors5 = new Array("Greg");    //创建一个包含1项的数组//5. 在使用Array构造函数时也可以省略new操作符
var colors6 = Array(3);
var names = Array("Greg");

var colors = ["red", "blue", "green"];    //创建一个包含三个字符串的数组
var names = [];    //创建一个空数组//在读取和设置数组的值时，要使用方括号并提供相应值的基于0的数字索引
alert(colors[0]);    //red
colors[2] = "black";
colors[3] = "brown";    //索引大于数组项时，自动增加一个
alert(colors.length);    //4

colors[99] = "black";
alert(colors.length);    //100

if(Array.isArray(colors)){alert("yes");
}

var colors = ["red", "blue", "green"];    //创建一个包含三个字符串的数组
alert(colors.toString());    //red,blue,green
alert(colors.valueOf());    //red,blue,green
alert(colors);    //red,blue,green

var colors = ["red", "blue", "green"];    //创建一个包含三个字符串的数组
alert(colors.join("||"));    //red||blue||green

var colors = ["red", "blue"];
var count = colors.push("green");
alert(count);    //3

count = colors.push("black");
alert(count);    //4var item = colors.pop();
alert(item);    //black

var colors = new Array();
var count = colors.push("red", "green");
alert(count);    //2

count = colors.push("black");
alert(count);    //3var item = colors.shift();
alert(item);    //red

count = colors.unshift("summer", "chen");
alert(count);    //4
alert(colors);    //summer,chen,green,black

var values = [0, 1, 3, 15, 5, 10];
values.reverse();
alert(values);    //10,5,15,3,1,0

values.sort();
alert(values);    //0,1,10,15,3,5

function compare(value1, value2){if(value1 < value2){return -1;}else if(value1 == value2){return 0;}else{return 1;}
}
var values = [0,15,10,5,1];
values.sort(compare);
alert(values);    //0,1,5,10,15

function compare(value1, value2){return value2 - value1;
}
var values = [0,15,10,5,1];
values.sort(compare);
alert(values);    //0,1,5,10,15

var colors = ["red", "green", "blue"];
var colors2 = colors.concat("yellow", ["black", "brown"]);alert(colors);    //red,green,blue
alert(colors2);    //red,green,blue,yellow,black,brown

var colors = ["red", "green", "blue", "black", "brown"];//1. 在只有一个参数的情况下，slice方法返回从该参数位置开始到当前数组末尾的所有项
var colors2 = colors.slice(1);
alert(colors2);    //green,blue,black,brown//2.有两个参数，该方法返回起始位置和结束位置之间的项，不包括结束位置的项
var colors3 = colors.slice(1,3);
alert(colors3);    //green,bluevar colors4 = colors.slice(3,1);
alert(colors4);    //空数组var colors5 = colors.slice(1,1);
alert(colors5);    //空数组var colors6 = colors.slice(5);
alert(colors6);    //空数组var colors7 = colors.slice(3, 15);
alert(colors7);    //black,brown

var colors = ["red", "green", "blue", "black", "brown"];//1. 删除： 可以删除任意数量的项，只需指定第一项的位置和要删除的项数。返回被删除的项
var colors2 = colors.splice(1,3);
alert(colors2);    //green,blue,black
alert(colors);    //red, brown//2.插入：提供三个参数:起始位置、0（要删除的项数）、要插入的项
var colors3 = colors.splice(1,0, "summer", "holiday");
alert(colors);    //red,summer,holiday,brownvar colors4 = colors.splice(-1,0, "summer", "holiday");//起始位置小于0时，按0计算
alert(colors);    //red,summer,holiday,summer,holiday,brownvar colors5 = colors.splice(10,0, "summer", "holiday");//起始位置大于数组长度时，按数组长度计算
alert(colors);    //red,summer,holiday,summer,holiday,brown,summer,holiday
alert(colors.length);    //8//3.替换：可以向指定位置插入任意数量的项，且同时删除任意数量的项，三个参数：起始位置，要删除的项数，要插入的项
var colors6 = colors.splice(1, 4, "green", "blue", "black");
alert(colors6);    //summer,holiday,summer,holiday
alert(colors);    //red,green,blue,black,brown,summer,holiday

var numbers = [1,2,3,4,5,4,3,2,1];alert(numbers.indexOf(4));    //3
alert(numbers.lastIndexOf(4));//5

alert(numbers.indexOf(4,4));//5
alert(numbers.lastIndexOf(4,4));//3

alert(numbers.indexOf(6));//-1
alert(numbers.lastIndexOf(6));//-1var person = {name: "Nicholas"};
var people = [{name: "Nicholas"}];var morePeople = [person];alert(people.indexOf(person));    //-1
alert(morePeople.indexOf(person));//0

var numbers = [1,2,3,4,5,4,3,2,1];var everyResult = numbers.every(function(item, index, array){return (item > 2);});
alert(everyResult);    //falsevar someResult = numbers.some(function(item, index, array){return (item > 2);});
alert(someResult);    //truevar filterResult = numbers.filter(function(item, index, array){return (item > 2);});
alert(filterResult);    // 3,4,5,4,3var mapResult = numbers.map(function(item, index, array){return (item + 2);});
alert(mapResult);    //3,4,5,6,7,6,5,4,3

var values = [1,2,3,4,5];
var sum = values.reduce(function(prev, cur, index, array){return prev + cur;});
alert(sum);    //15                    var sum2 = values.reduceRight(function(prev, cur, index, array){return prev + cur;});
alert(sum2);    //15