JavaScript高級程序設計:本地對象Array

    時間:2024-10-22 05:43:10 JavaScript 我要投稿
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    JavaScript高級程序設計:本地對象Array

      創建Array對象

      復制代碼 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:追加數組

      復制代碼 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組

      復制代碼 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結尾添加一個或多個項,pop用于刪除最后一個數組項,返回它作為函數值

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

      復制代碼 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:顛倒數組項的順序,sort:按數組項的值升序排列(首先要調用toString()方法,將所有值轉換成字符串)

      復制代碼 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]

      這是因為數字被轉換成字符串,然后按字符代碼進行比較的。

      splice

      splice:把數據項插入數組的中部

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

      復制代碼 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(第二個參數為0)就可以把數據插入指定位置,第一個參數為地始位置,第二個參數為0,第三個及以上參數為插入項

      復制代碼 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(第二個參數為不0)就可以把數據插入指定位置,第一個參數為地始位置,第二個參數為要刪除的項的個數,第三個及以上參數為插入項

      復制代碼 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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