javascript中没有像c#,java那样的哈希表(hashtable)的实现。在js中,object属性的实现就是hash表,因此只要在object上封装点方法,简单的使用obejct管理属性的方法就可以实现简单高效的hashtable。
首先简单的介绍关于属性的一些方法：
属性的枚举:
for/in循环是遍历对象属性的方法。如
var obj = { name : 'obj1', age : 20, height : '176cm' } var str = ''; for(var name in obj) { str += name + ':' + obj[name] + ' '; } alert(str);
输出为：name:obj1
age:20
height:176cm
检查属性是否存在:
in运算符可以用来测试一个属性是否存在。
this.containsKey = function ( key ) { return (key in entry); }
删除属性
使用delete运算符来删除一个对象的属性。使用delete删除的属性，for/in将不会枚举该属性，并且in运算符也不会检测到该属性。
delete entry[key]; delete obj.name;
下面是哈希表(hashtable)的js的实现方法：
function HashTable() { var size = 0; var entry = new Object(); this.add = function (key , value) { if(!this.containsKey(key)) { size ++ ; } entry[key] = value; } this.getValue = function (key) { return this.containsKey(key) ? entry[key] : null; } this.remove = function ( key ) { if( this.containsKey(key) && ( delete entry[key] ) ) { size --; } } this.containsKey = function ( key ) { return (key in entry); } this.containsValue = function ( value ) { for(var prop in entry) { if(entry[prop] == value) { return true; } } return false; } this.getValues = function () { var values = new Array(); for(var prop in entry) { values.push(entry[prop]); } return values; } this.getKeys = function () { var keys = new Array(); for(var prop in entry) { keys.push(prop); } return keys; } this.getSize = function () { return size; } this.clear = function () { size = 0; entry = new Object(); } }
测试：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>HashTable</title>
<script type="text/javascript" src="/js/jquery.js"></script>
<script type="text/javascript" src="/js/HashTable.js"></script>
<script type="text/javascript">
function MyObject(name)
{
this.name = name;
this.toString = function(){
return this.name;
}
}
$(function(){
var map = new HashTable();
map.add("A","1");
map.add("B","2");
map.add("A","5");
map.add("C","3");
map.add("A","4");
var arrayKey = new Array("1","2","3","4");
var arrayValue = new Array("A","B","C","D");
map.add(arrayKey,arrayValue);
var value = map.getValue(arrayKey);
var object1 = new MyObject("小4");
var object2 = new MyObject("小5");
map.add(object1,"小4");
map.add(object2,"小5");
$('#console').html(map.getKeys().join('|') + '<br>');
})
</script>
</head>
<body>
<div id="console"></div>
</body>
</html>
from:http://www.cnblogs.com/hyl8218/archive/2010/01/18/1650589.html