Calculate percentage from associative array in JS

Question

Suppose I have an array like this:

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

    [india: 7, indonesia: 3, usa: 1]

I need to get an array like [india: (7/11*100), indonesia: (3/11*100), usa: (1/11*100)] , ie, to get the percentage of each country value using a single loop in javascript. How can I achieve it ?

Answer 1

You can use array#reduce to sum up all values and then calculate percentages inside array#map

 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

If your objects is like this var arr = {india: 7, indonesia: 3, usa: 1}; , you can do it in this way.

 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

Loop through each key and reassigned the val like this:

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] is wrong, you need an object, like {india: 7, indonesia: 3, usa: 1}

So, I think you need an function to do what you need, simple:

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
}

Once you change the obj, you run getPercent(obj) , then you get a return, that is what's you need. May helpful.

Answer 5

So, suppose you have a valid array:

 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

You can make getters from object properties if it is allowed:

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());