JavaScript高级程序设计:本地对象Array

时间:2023-03-29 23:39:45 JavaScript 我要投稿
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JavaScript高级程序设计:本地对象Array

  创建Array对象

  复制代码 代码如下:

  //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:连接字符串

  复制代码 代码如下:

  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

  复制代码 代码如下:

  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:追加数组

  复制代码 代码如下:

  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:返回具有特定项的新数组

  复制代码 代码如下:

  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

  跟栈一样,Array提供了push和pop方法,push方法用于在Array结尾添加一个或多个项,pop用于删除最后一个数组项,返回它作为函数值

  复制代码 代码如下:

  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:删除数组中第一项,将其作为函数返回值,unshift:把一个项放在数组的第一个位置,然后把余下的项向下移动一个位置

  复制代码 代码如下:

  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:颠倒数组项的顺序,sort:按数组项的值升序排列(首先要调用toString()方法,将所有值转换成字符串)

  复制代码 代码如下:

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

  aColors.reverse();

  alert(aColors);//outputs ["red","green","blue"]

  aColors.sort();

  alert(aColors);//outputs ["blue","green","red"]

  注意:

  复制代码 代码如下:

  var aColors=[3,32,2,5];

  aColors.sort();

  alert(aColors);//outputs [2,3,32,5]

  这是因为数字被转换成字符串,然后按字符代码进行比较的。

  splice

  splice:把数据项插入数组的中部

  1、用作删除:只要声明两个参数,第一个参数为要删除的第一个项的位置,第二个参数为删除项的个数

  复制代码 代码如下:

  var aColors=["red","green","blue","yellow"];

  aColors.splice(0,2);

  alert(aColors);//outputs ["blue", "yellow"]

  2、用作插入:声明三个或以上参数(第二个参数为0)就可以把数据插入指定位置,第一个参数为地始位置,第二个参数为0,第三个及以上参数为插入项

  复制代码 代码如下:

  var aColors=["red","green","blue","yellow"];

  aColors.splice(2,0,"black","white");

  alert(aColors);//outputs ["red","green","black","white","blue", "yellow"]

  3、用作删除并插入:声明三个或以上参数(第二个参数为不0)就可以把数据插入指定位置,第一个参数为地始位置,第二个参数为要删除的项的个数,第三个及以上参数为插入项

  复制代码 代码如下:

  var aColors=["red","green","blue","yellow"];

  aColors.splice(2,1,"black","white");

  alert(aColors);//outputs ["red","green","black","white", "yellow"]

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