Sum of values in an array using jQuery [duplicate]

Solution 1:

To also handle floating point numbers:

(Older) JavaScript:

var arr = ["20.0","40.1","80.2","400.3"],
    n   = arr.length,
    sum = 0;
while(n--)
   sum += parseFloat(arr[n]) || 0;

ECMA 5.1/6:

var arr = ["20.0","40.1","80.2","400.3"],
    sum = 0;
arr.forEach(function(num){sum+=parseFloat(num) || 0;});

ES6:
```
var sum = ["20.0","40.1","80.2","400.3"].reduce((pv,cv)=>{
   return pv + (parseFloat(cv)||0);
},0);
```
The reduce() is available in older ECMAScript versions, the arrow function is what makes this ES6-specific.

I'm passing in 0 as the first pv value, so I don't need parseFloat around it — it'll always hold the previous sum, which will always be numeric. Because the current value, cv, can be non-numeric (NaN), we use ||0 on it to skip that value in the array. This is terrific if you want to break up a sentence and get the sum of the numbers in it. Here's a more detailed example:
```
let num_of_fruits = `
   This is a sentence where 1.25 values are oranges 
   and 2.5 values are apples. How many fruits are 
   there?
`.split(/\s/g).reduce((p,c)=>p+(parseFloat(c)||0), 0); 

// num_of_fruits == 3.75
```

jQuery:

var arr = ["20.0","40.1","80.2","400.3"],
    sum = 0;
$.each(arr,function(){sum+=parseFloat(this) || 0;});

What the above gets you:

ability to input any kind of value into the array; number or numeric string(123 or "123"), floating point string or number ("123.4" or 123.4), or even text (abc)
only adds the valid numbers and/or numeric strings, neglecting any bare text (eg [1,'a','2'] sums to 3)

You don't need jQuery. You can do this using a for loop:

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

You can use reduce which works in all browser except IE8 and lower.

["20","40","80","400"].reduce(function(a, b) {
    return parseInt(a, 10) + parseInt(b, 10);
})