Question

假设我有一个这样的数组：

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="6.1.0" targetFramework="net45" />
  <package id="Newtonsoft.Json" version="8.0.3" targetFramework="net45" />
  <package id="NUnit" version="3.7.0" targetFramework="net45" />
</packages>

我需要获得像var arr = []; arr["india"] = 7; arr["indonesia"] = 3; arr["usa"] = 1; [india: 7, indonesia: 3, usa: 1]这样的数组，即在javascript中使用单个循环获取每个国家/地区值的百分比。我怎样才能实现它？

Answer 1

您可以使用array#reduce汇总所有值，然后计算array#map

内的百分比

var arr = {};
arr["india"] = 7;
arr["indonesia"] = 3;
arr["usa"] = 1;

let sum = Object.keys(arr).reduce((s,k) => s += arr[k], 0);

var result = Object.keys(arr).map(k => ({[k] : (arr[k]/sum * 100).toFixed(2)}));

console.log(result);

Answer 2

如果您的对象与var arr = {india: 7, indonesia: 3, usa: 1};类似，则可以这样做。

var arr =  {india: 7, indonesia: 3, usa: 1};
var sum = 0;
//Finding the sum
for(key in arr){
    sum += arr[key];
}
console.log("Sum of the object values is = " + sum);
//Finding the average
for(key in arr){
    arr[key] = (arr[key]/sum)*100;
}
console.log(arr);

Answer 3

遍历每个键并重新分配val，如下所示：

var countries = [];
countries["india"] = 7;
countries["indonesia"] = 3;
countries["usa"] = 1;

for (var country in countries){
    if (countries.hasOwnProperty(country)) {
        countries[country] = (countries[country] / 11 * 100).toFixed(2)
    }
}

console.log(countries)

Answer 4

[india: 7, indonesia: 3, usa: 1]错误，您需要一个对象，例如{india: 7, indonesia: 3, usa: 1}

所以，我认为你需要一个能够做你需要的功能，简单：

var obj =  {india: 7, indonesia: 3, usa: 1}
const getPercent = (obj) {
    let sum = 0

    for (key in obj) {
        sum += obj[key]
    }

    for (key in obj) {
        obj[key] = (obj[key]/sum)*100
    }

    return obj
}

更改obj后，您运行getPercent(obj)，然后获得退货，这就是您需要的。可能有帮助。

Answer 5

所以，假设你有一个有效的数组：

var myArray = { 'key1': 2, 'key2': 5, 'key3': 14 };

/* iterates through an associative array, calculates each percentage and 
    adds it to a similar associative array 
    
    The percentages are not rounded
 */
function getPercentagePerKey(myArray) {
  var sum = getSum(myArray);
  var arrayWithPercentages = [];
  for (key in myArray) {
    val = myArray[key];
    percentage = (val / sum) * 100;
    arrayWithPercentages.push({key, percentage});
  }
  return arrayWithPercentages;  
}

/* returns the sum given from an 'associative' array */
function getSum(myArray) {
  var sum = 0;
  for (key in myArray) {
    sum += myArray[key];
  }
  return sum;
}

percentageArray = getPercentagePerKey(myArray);
console.log(percentageArray);

0: {key: "key1", percentage: 9.523809523809524}
1: {key: "key2", percentage: 23.809523809523807}
2: {key: "key3", percentage: 66.66666666666666}

Answer 6

如果允许，可以从对象属性中创建getter：

var arr = {};
arr["india"] = 7;
arr["indonesia"] = 3;
arr["usa"] = 1;

var sum = 0;
var percent = function(n){
  return function(){ return n/sum*100; }
}

for (var k in arr) {
  sum+=arr[k];
  arr[k]=percent(arr[k]);
}

console.log(arr.india());
console.log(arr.usa());
console.log(arr.indonesia());

从JS中的关联数组计算百分比

6 个答案: