《JavaScript高級程序設(shè)計》讀書筆記（九）：本地對象Array

創(chuàng)建Array對象

//one
var aValues=new Array();

//two
var aValues=new Array(20);

//three
var aColors=new Array();
aColors[0]="red";
aColors[1]="green";
aColors[2]="blue";

//four
var aColors=new Array("red","green","blue");

//five
var aColors=["red","green","blue"];

join && split

join:連接字符串

var aColors=["red","green","blue"];
alert(aColors.join(","));//outputs "red,green,blue"
alert(aColors.join("-spring-"));//outputs "red-spring-green-spring-blue"
alert(aColors.join("]["));//outputs "red][green][blue"

split:分拆字符串

var sColors="red,green,blue";
var aColors=sColors.split(",");//outputs ["red", "green", "blue"]
var redColors=aColors[0].split("");//outputs ["r", "e", "d"]

concat && slice

concat:追加數(shù)組

var aColors=["red","green","blue"];
var aColors2=aColors.concat("yellow","purple");
alert(aColors);//outputs ["red", "green", "blue"]
alert(aColors2);//outputs ["red", "green", "blue", "yellow", "purple"]

slice:返回具有特定項的新數(shù)組

var aColors=["red","green","blue","yellow","purple"];
var aColors2=aColors.slice(1);//outputs ["green","blue","yellow","purple"]
var aColors3=aColors.slice(1,4);//outputs ["green","blue","yellow"]

push && pop

跟棧一樣，Array提供了push和pop方法，push方法用于在Array結(jié)尾添加一個或多個項，pop用于刪除最后一個數(shù)組項，返回它作為函數(shù)值

var stack=new Array;
stack.push("red");
stack.push("green");
stack.push("blue");
alert(stack);//outputs ["red","green","blue"]
var vItem=stack.pop();
alert(vItem);//outputs ["blue"]
alert(stack);//otputs ["red","green"]

shift && unshift

shift:刪除數(shù)組中第一項，將其作為函數(shù)返回值，unshift:把一個項放在數(shù)組的第一個位置，然后把余下的項向下移動一個位置

var aColors=["red","green","blue"];
var vItem=aColors.shift();
alert(aColors);//outputs ["green","blue"]
alert(vItem);//outputs ["red"]
aColors.unshift("black");
alert(aColors);//outputs ["black","green","blue"]

reverse && sort

reverse:顛倒數(shù)組項的順序，sort:按數(shù)組項的值升序排列(首先要調(diào)用toString()方法，將所有值轉(zhuǎn)換成字符串)

var aColors=["blue","green","red"];
aColors.reverse();
alert(aColors);//outputs ["red","green","blue"]
aColors.sort();
alert(aColors);//outputs ["blue","green","red"]

注意：

var aColors=[3,32,2,5];
aColors.sort();
alert(aColors);//outputs [2,3,32,5]

這是因為數(shù)字被轉(zhuǎn)換成字符串，然后按字符代碼進行比較的。

splice

splice:把數(shù)據(jù)項插入數(shù)組的中部

1、用作刪除：只要聲明兩個參數(shù)，第一個參數(shù)為要刪除的第一個項的位置，第二個參數(shù)為刪除項的個數(shù)

var aColors=["red","green","blue","yellow"];
aColors.splice(0,2);
alert(aColors);//outputs ["blue", "yellow"]

2、用作插入：聲明三個或以上參數(shù)(第二個參數(shù)為0)就可以把數(shù)據(jù)插入指定位置，第一個參數(shù)為地始位置，第二個參數(shù)為0，第三個及以上參數(shù)為插入項

var aColors=["red","green","blue","yellow"];
aColors.splice(2,0,"black","white");
alert(aColors);//outputs ["red","green","black","white","blue", "yellow"]

3、用作刪除并插入：聲明三個或以上參數(shù)(第二個參數(shù)為不0)就可以把數(shù)據(jù)插入指定位置，第一個參數(shù)為地始位置，第二個參數(shù)為要刪除的項的個數(shù)，第三個及以上參數(shù)為插入項

var aColors=["red","green","blue","yellow"];
aColors.splice(2,1,"black","white");
alert(aColors);//outputs ["red","green","black","white", "yellow"]

posted @ 2012-02-26 16:09 artwl 閱讀(607) 評論(0) 收藏舉報

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