1

I've been following this post but I cannot get my array to add up all numbers in my array.

I use this:

 var array_new = [$(".rightcell.emphasize").text().split('€')];

to give me this array:

array_new: ,102.80,192.60,22.16

then I do this: 

var sum = array_new.reduce((a, b) => a + b, 0);
  console.log(sum); //gives me this 0,102.80,192.60,22.16

When all I want to do is add up the numbers, I get this result 0,102.80,192.60,22.16. Can anyone advise me?

artworkjpm
  • 1,255
  • 2
  • 19
  • 40
  • You are creating an array within an array by putting square brackets around your assignment of `array_new`. Try this: `var array_new = $(".rightcell.emphasize").text().split('€');` – Patrick Hund Nov 27 '18 at 15:43
  • Show us the relevant text in `$(".rightcell.emphasize")` – charlietfl Nov 27 '18 at 15:52

4 Answers4

2

Since your array is composed of undefined and a bunch of strings you have to parse the values to get the numbers. The answer would be:

var data = [,'102.80','192.60','22.16'];

console.log(data.reduce((r,c) => r + parseFloat(c), 0))

However if you do not want to deal with the parsing in that function you can make sure that your array comes out as array of numbers like this:

Array.from([$(".rightcell.emphasize").text().split('€')], (x) => parseFloat(x || 0))

Which would get your array ready for summation and without the need to parse inside the Array.reduce. So it would be something like this:

var strings = [,'102.80','192.60','22.16'];
var numbers = Array.from(strings, (x) => parseFloat(x || 0))

console.log(numbers.reduce((r,c) => r + c, 0))

But in your case it would be shorter since you would do the first 2 lines as one as shown in the 2nd code snippet.

Akrion
  • 18,117
  • 1
  • 34
  • 54
0

That's because your original array is a string array.

Use parseFloat to create numbers from the strings.

var strArr = ['102.80','192.60','22.16'];
var sum = strArr.reduce((a,b) => a + parseFloat(b),0); // 317.56
Amir Popovich
  • 29,350
  • 9
  • 53
  • 99
0

Your elements in the array are treated as strings, therefore the + in your reduce function concatenates the array elements into another string. Try to use parseFloat() to treat them as numbers:

var sum = array_new.reduce((a, b) => a + parseFloat(b), 0);

EDIT: Thanks to charlietfl who mentioned, that parseFloat(a) is redundant, fixed it.

EDIT: (since you already deleted your comment, here would be the solution for your problem): in your case this solution won't work, because one of your array elements is "" (an empty string) which can't be treated as a number, so you could map your array values before you try to add them up:

array_new.map(a => (a == "") ? "0" : a);
Nyze
  • 16
  • 3
0

in javascript, you can concat numbers by + or strings as well . I will give you an example : 

var x = "2" + "1"; // x = 21
var x = 2 + 1 ; // x = 3

You can look to this.

You should convert your array to integers (parseInt) or floats(parseFloat) in this function array_new.reduce((a, b) => a + b, 0); It will be something like 

array_new.reduce((a, b) => a + parseInt(b), 0);//or
array_new.reduce((a, b) => a + parseFloat(b), 0);
Houssein Zouari
  • 712
  • 6
  • 18