摘要：屬性名描述為對(duì)象添加屬性方法返回?cái)?shù)組對(duì)象引用返回?cái)?shù)組元素?cái)?shù)目方法名描述返回更改原數(shù)組連接多個(gè)數(shù)組連接后新數(shù)組將數(shù)組中所有元素合為一個(gè)字符串。

new Array();
new Array(size);
new Array(element0, element1, ..., elementn);
var arr = []; //字面量方式

經(jīng)測(cè)試用字面量方式跟new Array()耗時(shí)差不多，使用習(xí)慣的差距吧~ new Array()能初始化長(zhǎng)度~

prototype 向?qū)ο筇砑訉傩院头椒?/p>

function em(A,B)
{
    this.A = A;
    this.B = B;
}
var e = new em("AA","BB");
em.prototype.C = null;
e.C = 20000;
console.log(e.C); //20000
console.log(e); //em {A:"AA" , B:"BB" , C : 20000 }

constructor 返回對(duì)創(chuàng)建此對(duì)象的數(shù)組函數(shù)的引用

function employee(name,job)
{
    this.name = name;
    this.job = job;
}
var bill = new employee("Bill");
console.log(typeof bill.constructor); // function
console.log(bill.constructor); //function employee(name){this.name=name;this.job=job;}

concat() 連接兩個(gè)或更多的數(shù)組（返回被連接數(shù)組的副本）

var arr = [1, 2, 3];
var arr1 = [6, 7];
console.log(arr.concat(4, 5, arr1)); //[1, 2, 3, 4, 5, 6, 7]

join() 把數(shù)組的所有元素放入一個(gè)字符串，元素通過(guò)指定的分隔符分隔。

var arr = ["item 1", "item 2", "item 3"];
var list = "
" + arr.join("
") + "
"; //"
item 1
item 2
item 3
"

toString() 數(shù)組轉(zhuǎn)換為字符串（與無(wú)參的 join()方法返回的串相同）

var arr = new Array(3)
arr[0] = "A"
arr[1] = "B"
arr[2] = "C"
console.log(arr.toString()); //"A,B,C"

pop() 刪除數(shù)組的最后一個(gè)元素，數(shù)組長(zhǎng)度減 1，并返回被刪除的元素的值

若數(shù)組為空，則pop()返回undefined值

var arr = ["A", "B", "C"];
console.log(arr); //["A", "B", "C"]
console.log(arr.pop()); //"C"
console.log(arr); //["A", "B"]

push() 向數(shù)組的末尾添加一個(gè)或更多元素，并返回新的長(zhǎng)度

var arr = ["A", "B", "C"];
console.log(arr); //["A", "B", "C"]
console.log(arr.push("D")); //4
console.log(arr); ////["A", "B", "C" , "D"]

reverse() 顛倒數(shù)組中元素的順序

var arr = ["A", "B", "C"];
arr.reverse();
console.log(arr);// ["C", "B", "A"]

slice(start,end) 從數(shù)組中返回選定的子數(shù)組

var arr = ["A", "B", "C"];
// 從第一個(gè)元素開(kāi)始截取到數(shù)組結(jié)尾
console.log(arr.slice(1)); //["B", "C"]
console.log(arr); //["A", "B", "C"]

splice() 刪除元素，并向數(shù)組添加新元素
(直接對(duì)數(shù)組操作)

① 刪除指定范圍的數(shù)組元素：

var arr = new Array(6);
    arr[0] = "A"; 
    arr[1] = "B";
    arr[2] = "C";
    arr[3] = "D";
    arr[4] = "E";
    arr[5] = "F";
console.log(arr); //["A", "B", "C", "D", "E", "F"]
// 刪除第三個(gè)元素以后的三個(gè)數(shù)組元素(包含第三個(gè)元素)
console.log(arr.splice(2, 3));  //["C", "D", "E"]
console.log(arr); //["A", "B", "F"]

② 從指定下標(biāo)開(kāi)始插入指定元素(元素個(gè)數(shù)不限)：

    var arr = new Array(6);
    arr[0] = "A"; 
    arr[1] = "B";
    arr[2] = "C";
    arr[3] = "D";
    arr[4] = "E";
    arr[5] = "F";
console.log(arr); //["A", "B", "C", "D", "E", "F"]
console.log(arr.splice(2, 0, "AA","BB")); // []
console.log(arr);//["A", "B", "AA" , "BB" , "C", "D", "E", "F"]

③ 刪除指定范圍的數(shù)組元素，并用指定元素替換(元素個(gè)數(shù)不限)：

var arr = new Array(6);
    arr[0] = "A"; 
    arr[1] = "B";
    arr[2] = "C";
    arr[3] = "D";
    arr[4] = "E";
    arr[5] = "F";
console.log(arr);//["A", "B", "C", "D", "E", "F"]
console.log(arr.splice(2, 1, "AA","BB")); // ["C"]
console.log(arr); //["A", "B", "AA", "BB", "D", "E", "F"]

sort() 對(duì)數(shù)組的元素進(jìn)行排序
對(duì)數(shù)組的引用

數(shù)組在原數(shù)組上進(jìn)行排序，不生成副本。該方法默認(rèn)是按照字符編碼(ASCII)的順序進(jìn)行排序的

var arr = new Array(3);
    arr[0] = "D";
    arr[1] = "S";
    arr[2] = "A";
console.log(arr); //["D", "S", "A"]
console.log(arr.sort()); //["A", "D", "S"]

自行指定排序規(guī)則。如下：

var arr = new Array(6);
    arr[0] = 10;
    arr[1] = 5;
    arr[2] = 40;
    arr[3] = 25;
    arr[4] = 1000;
    arr[5] = 1;
console.log(arr); //[10, 5, 40, 25, 1000, 1]
//升序
console.log(arr.sort(function (a, b) {return a - b;}));// [1, 5, 10, 25, 40, 1000]

valueOf() 返回相應(yīng)的原始值

var arr = new Array(2);
    arr[0] = 10
    arr[1] = 5
console.log(arr); //[10, 5]
console.log(typeof arr.valueOf()); //object
console.log(arr.valueOf()); //[10, 5]

shift() 刪除并返回?cái)?shù)組的第一個(gè)元素

var arr = ["A", "B", "C"];
console.log(arr); //["A", "B", "C"]
console.log(arr.shift()); //A
console.log(arr); //["B", "C"]

unshift() 向數(shù)組的開(kāi)頭添加一個(gè)或更多元素，并返回新的長(zhǎng)度

var arr = ["A", "B", "C"];
console.log(arr); //["A", "B", "C"]
console.log(arr.unshift("AA")); //4
console.log(arr);//["AA", "A", "B", "C"]

indexOf() 返回元素在數(shù)組中出現(xiàn)位置

額 之前一直以為只有string有這個(gè)方法... 補(bǔ)上補(bǔ)上

var arr = ["orange", "2016", undefined , null ,NaN];
console.log(arr.indexOf("orange")); //0
console.log(arr.indexOf("o")); //-1
console.log(arr.indexOf("2016"));  //1
console.log(arr.indexOf(2016));  //-1
console.log(arr.indexOf("undefined"));  //-1
console.log(arr.indexOf(null));  //3
console.log(arr.indexOf(NaN));  //-1

以上只是為了論證這里的indexOf使用的是嚴(yán)格匹配（===），不會(huì)像string的indexOf一樣隱式轉(zhuǎn)換成字符串進(jìn)行匹配~