Javascript 中 HashMap 实现

来源：互联网发布：沈飞知乎编辑：程序博客网时间：2024/06/06 13:21

诸如HashMap、Stack、Queue都可以通过操作JS数组进行实现。下面我们首先参照Javascript官方使用手册对JS Array对象中的一些常用函数进行解释一下，以便进行下面的数据结构的实现(JS Array对象类似于堆栈的元素进出栈顺序)：
Push : 添加一个元素
Reverse:将数组元素进行逆序
Shift:移除数组中第一个元素(下标为0)

Pop:弹出最后一个元素(下标为array.length-1)

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head>  <title> New Document </title>  <script type="text/javascript">     function HashMap(){ this.source = new Array(); this.length = 0;   };   /*将函数列表(实为JSON数据)映射到HashMap的prototype属性中*/  function Apply(o, c){      if(o && c && typeof c == 'object'){for(var p in c){o[p] = c[p];}}return o;  };  Apply(HashMap.prototype,{   /*获取元素的个数*/size : function(){ return  this.length },/*查看是否存在该key值*/containsKey :function (key) {          if(this.source[key])  return true;else           return false;      },     /*查看是否存在该value值*/containsValue :function (value) {          for (var key in this.source) {              if (this.source[key] == value) {                  return true;              }          }          return false;      }, /*存入数据   返回值如果为false表示该key值已经存过数据,我们会替换前一条数据*/put : function(key,value)    {   var tag = this.containsKey(key);   this.length += ((tag)? 0: 1);   this.source[key] = value;          return !tag;     },    /*根据key读取数据*/    get :  function(key)       { return this.source[key];       },     /* 根据key值删除HashMap中元素,返回删除元素的value */       remove : function(key)        {        var value = this.source[key];         if( this.containsKey(key) && ( delete this.source[key] ) )            {                this.length --;            }            return value;     }, /*清除所有数据*/ clear : function() {   delete this.source;   this.source = new Array();   this.length = 0;   return 0; },      obj2str :function(o) {          var r = [];          if (typeof o == "string")              return "\"" + o.replace(/([\'\"\\])/g, "\\$1").replace(/(\n)/g, "\\n").replace(/(\r)/g, "\\r").replace(/(\t)/g, "\\t") + "\"";          if (typeof o == "object") {              for (var i in o)                  r.push("\"" + i + "\":" + this.obj2str(o[i]));              if (!!document.all && !/^\n?function\s*toString\(\)\s*\{\n?\s*\[native code\]\n?\s*\}\n?\s*$/.test(o.toString)) {                  r.push("toString:" + o.toString.toString());              }              r = "{" + r.join() + "}";              return r;          }          return o.toString();       }, /*将数据以JSON字串形式输出*/ toString : function() {     return this.obj2str(this.source); }    });  var hsp = new HashMap(); document.writeln(hsp.put('a',"apple"));   //true document.writeln(hsp.put('b',"boy"));     //true document.writeln(hsp.put('c',"cat"));    //true document.writeln(hsp.put('a',"replaceApple"));  //false document.writeln(hsp.get("a"));   //"replaceApple" document.writeln(hsp.size());     //3 document.writeln(hsp.containsValue('cat'));  //true document.writeln(hsp.containsKey('a'));  //true document.writeln(hsp.remove('a'));    //"replaceApple" document.writeln(hsp.toString());   //"{"b":"boy","c":"cat"}" document.writeln(hsp.clear());    //2 document.writeln(hsp.toString());   "{}"   </script> </head> <body>   </body></html>

注：Stack和Queue的实现可以参看： http://blog.csdn.net/wdxgdiy/article/details/8877565 写的不错

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