Analysis of JavaScript repeated element processing methods [statistical number, calculation, deduplication, etc.]_javascript skills

This article mainly introduces the JavaScript repeated element processing method, combined with the example form to analyze javascript the number statistics, calculation and deduplication of repeated elements in strings and arrays For related operating techniques, friends who are interested in JavaScript can refer to

. This article describes how to handle repeated elements in JavaScript with examples. Share it with everyone for your reference, the details are as follows:

Determine the character that appears most often in a string, and count the number

//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);

Written by A method to find the byte length of a string

Assumption:

One English character occupies one byte, and one Chinese character occupies two bytes

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"));

Write a method to remove duplicate elements from an array

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());

Write a method to remove all duplicate elements from a string

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());

PS: Here are several deduplication tools for your reference:

Online duplicate removal tool:
http://tools.jb51.net/code/quchong

Online Text deduplication tool:
http://tools.jb51.net/aideddesign/txt_quchong

The above is all the content of this article, I hope it can be Bringing help to everyone! !

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