對象聯接的Javascript數組重復項

Question

我需要按國家/地區代碼查找重復項並將它們合並為一個對象

數組結構為：

[{...},{...}]

對象

{Country_Code: "RU", Country: "Russia", Provider: "Shell1", Price: "0.123"},
{Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856"},
{Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563"},
{Country_Code: "RU", Country: "Russia", Provider: "Shell2", Price: "0.90890"},
{Country_Code: "RU", Country: "Russia", Provider: "Shell3", Price: "0.90"}

我需要獲取對象數組

[{Country_Code: "RU", Country: "Russia", Provider: "Shell1 - 0.123</br>Shell2 - 0.90890</br>Shell3 - 0.90", Price: "0.123"},
{Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856"},
{Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563"}]

如果想必一定是這樣

var NewArr =[],NewObj ={};
data.forEach(function(dataItem,index) {
    CC = dataItem.Country_Code;
    counts[CC]= (counts[CC]||0) + 1; // Count duplicates
        if(counts[CC]>1){
            NewObj.Country_Code = dataItem.Country_Code;
            NewObj.Country = dataItem.Country;
            NewObj.Provider = dataItem.Provider + " - " + dataItem.Price + "</br>";
            NewObj.Price = dataItem.Price;
            NewArr[indexOfDup] = NewObj; //but how to know index?
        }else{
            NewArr.push(data[index]);
        }

});

但這是錯誤的，那么如何編寫正確的語法呢？

Answer 1

您將需要array.reduce 。 使用array.reduce返回一個數組。 在此數組中，使用findIndex檢查是否存在country_code存在的對象。 如果存在，則更新屬性值

 let x = [{ Country_Code: "RU", Country: "Russia", Provider: "Shell1", Price: "0.123" }, { Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856" }, { Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563" }, { Country_Code: "RU", Country: "Russia", Provider: "Shell2", Price: "0.90890" }, { Country_Code: "RU", Country: "Russia", Provider: "Shell3", Price: "0.90" } ] let m = x.reduce(function(acc, curr) { let findIndex = acc.findIndex((item) => { return item['Country_Code'] === curr['Country_Code'] }); if (findIndex === -1) { acc.push(curr) } else { acc[findIndex].Provider = acc[findIndex].Provider + ' - ' + acc[findIndex].Price + '<br/>' + curr.Provider + ' - ' + curr.Price } return acc; }, []); console.log(m) 

Answer 2

'use strict';

const data = [
  {Country_Code: "RU", Country: "Russia", Provider: "Shell1", Price: "0.123"},
  {Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856"},
  {Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563"},
  {Country_Code: "RU", Country: "Russia", Provider: "Shell2", Price: "0.90890"},
  {Country_Code: "RU", Country: "Russia", Provider: "Shell3", Price: "0.90"}
];

// create a hashmap by country code
const dataPerCountry = data.reduce((dataCountry, currentValue) => {
  const item = {  }
  if (dataCountry[currentValue.Country_Code]) {
    dataCountry[currentValue.Country_Code].Provider.push(currentValue.Provider);
  } else {
    dataCountry[currentValue.Country_Code] = { 
      ...currentValue,
      Provider: [currentValue.Provider],
    };
  }

  return dataCountry;
}, {});

/** 
 * Transform the hasmap into an array of objects used by the view,
 * also applying the transformation to concat the Providers
 **/
const reducedCountriesVO = Object.keys(dataPerCountry).map((countryCode) => {
  const dataCountry = { ...dataPerCountry[countryCode] };

  dataCountry.Provider = dataCountry.Provider.join('<br>-');

  return dataCountry;
});

console.log(reducedCountriesVO);

Answer 3

有很多解決方法。 這是我的小貢獻，我提出的算法不使用任何搜索算法。 因此，對於大型陣列，它可以相對快速地執行。

var myArray = [{Country_Code: "RU", Country: "Russia", Provider: "Shell1", Price: "0.123"},
{Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856"},
{Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563"},
{Country_Code: "RU", Country: "Russia", Provider: "Shell2", Price: "0.90890"},
{Country_Code: "RU", Country: "Russia", Provider: "Shell3", Price: "0.90"}];


var groupByCountryCode = function(xs, key) {
  return xs.reduce(function(rv, x) {
    if(rv[x[key]]){
      // It has found more than one instance

      rv[x[key]][0].Provider += " " + x.Provider;
    }else{
      rv[x[key]] = [];
      rv[x[key]].push(x);
    }
    return rv;
  }, {});
};

var grouppedElementsByKey = groupByCountryCode(myArray,"Country_Code");

var grouppedArray =   Object.keys(grouppedElementsByKey).map(function(key){
  return grouppedElementsByKey[key][0];
});


console.log(grouppedArray);

最終輸出將像您所要求的那樣。

Answer 4

這是使用reduce一種解決方案。 首先，我使用具有多個值的屬性的數組創建了一個地圖結構。 然后，我使用有組織的結構來格式化數據，使其看起來像您想要的樣子：

 var data = [{ Country_Code: "RU", Country: "Russia", Provider: "Shell1", Price: "0.123" }, { Country_Code: "EN", Country: "Russia", Provider: "Shell", Price: "0.76856" }, { Country_Code: "RO", Country: "Russia", Provider: "Shell", Price: "0.563" }, { Country_Code: "RU", Country: "Russia", Provider: "Shell2", Price: "0.90890" }, { Country_Code: "RU", Country: "Russia", Provider: "Shell3", Price: "0.90" }]; //First, make a map structure for organization var map = data.reduce((map, el) => { let provider = []; let price = []; if (map[el.Country_Code]) { provider = map[el.Country_Code].Provider; price = map[el.Country_Code].Price; } provider.push(el.Provider); price.push(el.Price); map[el.Country_Code] = { Country_Code: el.Country_Code, Country: el.Country, Provider: provider, Price: price } return map; }, {}); //Use the data map to display the data however you want var formatted = Object.values(map).map((el) => { return { Country_Code: el.Country_Code, Country: el.Country, Provider: el.Provider.reduce((str, providerEl, idx) => { return str += `${providerEl} - ${el.Price[idx]}</br>`; }, ''), Price: el.Price[0] //this doesnt make sense IMO, but will leave it since that's how you asked for the data } }); console.log(Object.values(formatted)); //{Country_Code: "RU", Country: "Russia", Provider: "Shell1 - 0.123</br>Shell2 - 0.90890</br>Shell3 - 0.90", Price: "0.123"} 

Answer 5

您可以在此處使用use array.indexOf(someValue)屬性。