JavaScript重复元素处理方法分析【统计个数、计算、去重复等】

//将字符串的字符保存在一个hash table中，key是字符，value是这个字符出现的次数var str = "abcdefgaddda";var obj = {};for (var i = 0, l = str.length; i < l; i++) {  var key = str[i];  if (!obj[key]) {   obj[key] = 1;  } else {   obj[key]++;  }}/*遍历这个hash table，获取value最大的key和value*/var max = -1;var max_key = "";var key;for (key in obj) {  if (max < obj[key]) {   max = obj[key];   max_key = key;  }}alert("max:"+max+" max_key:"+max_key);

function GetBytes(str){  var len = str.length;  var bytes = len;  for(var i=0; i<len; i++){    if (str.charCodeAt(i) > 255) bytes++;  }  return bytes;}alert(GetBytes("你好,as"));

var arr = [1 ,1 ,2, 3, 3, 2, 1];Array.prototype.unique = function(){  var ret = [];  var o = {};  var len = this.length;  for (var i=0; i<len; i++){    var v = this[i];    if (!o[v]){      o[v] = 1;      ret.push(v);    }  }  return ret;};alert(arr.unique());

var arr = '112332454678';String.prototype.unique = function(){  var ret = [];  var o = {};  var len = this.length;  for (var i=0; i<len; i++){    var v = this[i];    if (!o[v]){      o[v] = 1;    } else {      o[v] = 2;    }  }  for(var k in o){    if (o[k]==1) {      ret.push(k);    };  }  return ret;};alert(arr.unique());