How to find the sum of an array of numbers

Question

Given an array [1, 2, 3, 4], how can I find the sum of its elements? (In this case, the sum would be 10.)

I thought $.each might be useful,

Answer 1

If you happen to be using Lodash you can use the sum function

array = [1, 2, 3, 4];
sum = _.sum(array); // sum == 10

Answer 2

var arr = [1,2,3,4];
var total=0;
for(var i in arr) { total += arr[i]; }

Answer 3

When the array consists of strings one has to alter the code. This can be the case, if the array is a result from a databank request. This code works:

alert(
["1", "2", "3", "4"].reduce((a, b) => Number(a) + Number(b), 0)
);

Here, ["1", "2", "3", "4"] ist the string array and the function Number() converts the strings to numbers.

Answer 4

I am a beginner with JavaScript and coding in general, but I found that a simple and easy way to sum the numbers in an array is like this:

    var myNumbers = [1,2,3,4,5]
    var total = 0;
    for(var i = 0; i < myNumbers.length; i++){
        total += myNumbers[i];
    }

Basically, I wanted to contribute this because I didn't see many solutions that don't use built-in functions, and this method is easy to write and understand.

Answer 5

arr.reduce(function (a, b) {
    return a + b;
});

Reference: Array.prototype.reduce()

Answer 6

Use a for loop:

const array = [1, 2, 3, 4];
let result = 0;

for (let i = 0; i < array.length - 1; i++) {
  result += array[i];
}

console.log(result); // Should give 10

Or even a forEach loop:

const array = [1, 2, 3, 4];
let result = 0;

array.forEach(number => {
  result += number;
})

console.log(result); // Should give 10

For simplicity, use reduce:

const array = [10, 20, 30, 40];
const add = (a, b) => a + b
const result = array.reduce(add);

console.log(result); // Should give 100