JavaScript高級程序設(shè)計(jì) 讀書筆記之九本地對象Array

更新時(shí)間：2012年02月27日 23:50:56 作者：

本地對象Array，數(shù)組等操作函數(shù)

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

復(fù)制代碼代碼如下:

 
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

復(fù)制代碼代碼如下:

 
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

復(fù)制代碼代碼如下:

 
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(xiàng)的新數(shù)組

復(fù)制代碼代碼如下:

 
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(gè)或多個(gè)項(xiàng)，pop用于刪除最后一個(gè)數(shù)組項(xiàng)，返回它作為函數(shù)值

復(fù)制代碼代碼如下:

 
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(xiàng)，將其作為函數(shù)返回值，unshift:把一個(gè)項(xiàng)放在數(shù)組的第一個(gè)位置，然后把余下的項(xiàng)向下移動一個(gè)位置

復(fù)制代碼代碼如下:

 
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(xiàng)的順序，sort:按數(shù)組項(xiàng)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)

復(fù)制代碼代碼如下:

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

注意：

復(fù)制代碼代碼如下:

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

這是因?yàn)閿?shù)字被轉(zhuǎn)換成字符串，然后按字符代碼進(jìn)行比較的。

splice
splice:把數(shù)據(jù)項(xiàng)插入數(shù)組的中部

1、用作刪除：只要聲明兩個(gè)參數(shù)，第一個(gè)參數(shù)為要刪除的第一個(gè)項(xiàng)的位置，第二個(gè)參數(shù)為刪除項(xiàng)的個(gè)數(shù)

復(fù)制代碼代碼如下:

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

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

復(fù)制代碼代碼如下:

 
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(gè)或以上參數(shù)(第二個(gè)參數(shù)為不0)就可以把數(shù)據(jù)插入指定位置，第一個(gè)參數(shù)為地始位置，第二個(gè)參數(shù)為要刪除的項(xiàng)的個(gè)數(shù)，第三個(gè)及以上參數(shù)為插入項(xiàng)

復(fù)制代碼代碼如下:

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

您可能感興趣的文章: