How to properly sum array in JavaScript

Question

I have a problem to get the sum of my array. I'm using Adwords script, which works like javascript. I can "print out" my array which shows the numbers i'm interested in. Like [23369.2, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]. But when I'm adding them together using my for-loop the results produce NaN (Not-a-Number). I don't really know what to do.

var spend = [];

function main() {
  var campaignsIterator = AdWordsApp.campaigns().get();
  var sum;

  while(campaignsIterator.hasNext()) {
    var campaigns = campaignsIterator.next();
    var stats = campaigns.getStatsFor("THIS_MONTH");
    var costPerAdG = stats.getCost();

    spend.push(costPerAdG);
  }

  for(var i in spend){
    sum += parseInt(spend[i]);
  }

  Logger.log(spend);
}

Nina Scholz · Accepted Answer · 2017-02-21 15:09:48Z

2

You need to initialize sum with 0, otherwise the value is undefined.

If you add a numerical value, you get NaN - if you add a string, then the result is 'undefined' + string.

var sum = 0;
//      ^^^

var a,
    b = 0;

a += 1;
b += 1;
console.log(a); // NaN
console.log(b); // 1

edited Feb 21, 2017 at 15:09

answered Feb 21, 2017 at 14:58

Nina Scholz

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1 Comment

user7302419 Over a year ago

Thanks! Works perfectly now.

jeffdill2 · Accepted Answer · 2017-02-21 15:36:40Z

0

You could also define sum and actually sum your array in a single clean one-liner:

var sum = spend.reduce((a, b) => a + b);

edited Feb 21, 2017 at 15:36

answered Feb 21, 2017 at 15:18

jeffdill2

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Comments

treeseal7 · Accepted Answer · 2017-02-21 23:11:32Z

0

here's a simple function for getting the sum of an array

function sumarr(arr){
    return arr.reduce(add, 0);
}

arr=[23369.2, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

sumarr(arr)

answered Feb 21, 2017 at 23:11

treeseal7

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