Object returning NaN when sum values

Question

I\'ll admit I\'m weak in JavaScript and JSON. I\'ve spent a lot of time attempting to figure out why numbers from my objects returns NaN when they are added together. With t

Answer 1

you need to initialize jan first

var jan = 0; 

here's the example - link

Answer 2

I like this approach. It basically sets the value to 0 on the first iteration when jan doesn't exist.

jan = (jan || 0) + parseFloat(data[i].jan);

Answer 3

var jan = 0; //this should solve it

for (var i=0;i<data.length;i++){ 
    if(data[i].jan != null){    
        jan += parseFloat(data[i].jan);
        console.log(jan);
    }
}

Try this should solve it :)

Explanation as quoted by DON in comments below:

var jan; this will declare variable as undefined, so when you try to add values with undefined you will get as NaN, so the answer here with var jan = 0 will work – DON