我如何在数字数组中找到重复项+计数器如何在内部重复每个数字

Question

我需要找到数组内大于或等于两次的重复项。 例如，如果我有字符串数组，这将起作用

var arrStr = 'i do   as as     becasue               i do as';


function CheckDuplicates(sentence)
{
  let arr = sentence.split(" ");
  let counter = {};
  let duplicates = [];

  for(let i = 0;i < arr.length;i++)
  {
    let item = arr[i];
    counter[item] = counter[item] >= 1 ? counter[item] += 1 : 1;
    if(item != "")
    {
      if(counter[item] == 2)
      {
        duplicates.push(item);
      }
    }
  }

  Object.keys(counter)
  .filter(key => !duplicates.includes(key))
  .forEach(k => delete counter[k]);

  return {
    duplicates: duplicates,
    counter: counter
  };

}


let r = CheckDuplicates(arrStr);

c.log(r.duplicates);
c.log(r.counter);

结果我进入控制台

["as", "i", "do"]
{i: 2, do: 2, as: 3}

但是使用相同的代码，如果我尝试使用数字数组执行此操作，我会在c.log(r.counter);中得到 {}

我不知道为什么包含在这种情况下无法使用数字

var arr = [9, 9,  9 ,111, 2, 3, 4, 4, 5, 7 , 7];

function CheckDuplicates(sentence)
{
  let counter = {};
  let duplicates = [];

  for(let i = 0;i < arr.length;i++)
  {
    let item = arr[i];
    counter[item] = counter[item] >= 1 ? counter[item] += 1 : 1;
    if(item != "")
    {
      if(counter[item] == 2)
      {
        duplicates.push(item);
      }
    }
  }

  Object.keys(counter)
  .filter(key => !duplicates.includes(key))
  .forEach(k => delete counter[k]);

  return {
    duplicates: duplicates,
    counter: counter
  };

}


let r = CheckDuplicates(arr);

c.log(r.duplicates);
c.log(r.counter);

所以在控制台中我得到

[9, 4, 7]
{}

Answer 1

Object.keys将键作为字符串返回，并且includes类型相等性检查。

注释行是我唯一更改的内容，并且您的代码工作正常（我在推入duplicates时转换为字符串，但您也可以在使用时修复它includes ）

 var arr = [9, 9, 9,111, 2, 3, 4, 4, 5, 7, 7]; function CheckDuplicates(sentence) { let counter = {}; let duplicates = []; for(let i = 0;i < arr.length;i++) { let item = arr[i]; counter[item] = counter[item] >= 1? counter[item] += 1: 1; if(item.= "") { if(counter[item] == 2) { duplicates;push(`${item}`). // casting to string } } } Object.keys(counter).filter(key =>.duplicates;includes(key)):forEach(k => delete counter[k]), return { duplicates: duplicates; counter; counter }. } let r = CheckDuplicates(arr). console;log(r.duplicates). console;log(r.counter);