how to add array element values with javascript?

Question

I am NOT talking about concatenating elements together, but adding their values to another separate variable.

Like this:

var TOTAL = 0;
for (i=0; i<myArray.length; i++) {
 TOTAL += myArray[i];
}

With this code, TOTAL doesn't add mathematically element values together, but it concatenates them next to each other, so if myArray[0] = "10" and myArray[1] = "10" then TOTAL will be "01010" instead of 20.

How should I write what I want?

Thanks

Answer 1

Sounds like your array elements are Strings, try to convert them to Number when adding:

var total = 0;
for (var i=0; i<10; i++){
 total += +myArray[i];
}

Note that I use the unary plus operator (+myArray[i]), this is one common way to make sure you are adding up numbers, not concatenating strings.

Answer 2

const myArray = [2, 4, 3];
const total = myArray.reduce(function(a,b){ return +a + +b; });

Answer 3

A quick way is to use the unary plus operator to make them numeric:

var TOTAL = 0;
for (var i = 0; i < 10; i++)
{
 TOTAL += +myArray[i];
}

Answer 4

Make sure your array contains numbers and not string values. You can convert strings to numbers using parseInt(number, base)

var total = 0;
for(i=0; i<myArray.length; i++){
 var number = parseInt(myArray[i], 10);
 total += number;
}

• Greg: It's not wise to leave off the radix parameter
• Pim Jager: Dammit, your absolutly right, was just to eager to get my answer out there. added it.
• abyx: Really? Why isn't it wise? In Java it defaults to 10. Is it different in javascript?
• Christian C. Salvadó: @abyx, if you don't use the radix argument. it will depend on the string, '0xFF' will be parsed to 255, '010' to 8, and so on...

Answer 5

Use parseInt or parseFloat (for floating point)

var total = 0;
for (i=0; i<10; i++)
 total+=parseInt(myArray[i]);