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JavaScript高級程序設(shè)計:本地對象Array

時間:2023-03-29 23:39:45 JavaScript 我要投稿
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JavaScript高級程序設(shè)計:本地對象Array

  創(chuàng)建Array對象

  復(fù)制代碼 代碼如下:

  //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

  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,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

  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)

  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)

  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

  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

  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"]

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