Adding digits in an array with JavaScript

Question

var myArr = [ '111' , '222' , '333' ] ;

I would like this to become [3, 6, 9] essentially summing up the digits. Would a nested for-loop or map be the best route to achieve this?

OP, while you have a number of answers here, for future reference it's important that you attempt the solution yourself and if you run into problems post that as your question so we can see what you've tried, rather than using SO as a coding service. — Andy
– Andy, Commented Apr 9, 2016 at 1:03

DarkAjax · Accepted Answer · 2016-04-09 00:31:16Z

2

I'd maybe do something like this:

myArr.map(function(a){
    var temp = 0;
    a.split('').forEach(function(b){
        temp += parseInt(b,10);
    });
    return temp;
});

answered Apr 9, 2016 at 0:31

DarkAjax

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Comments

score 2 · Accepted Answer · 2016-04-09 00:37:06Z

2

You can map and evaluate the sum reducing the regex matches for each digit:

var myArr = [ '111' , '222' , '333' ];

var result = myArr.map(function(text){
    return text.match(/\d/g).reduce(function(x, y){
        return +y + x;
    }, 0);
});

O.innerHTML = JSON.stringify(result);

<pre id=O>

Hope it helps ;)

edited Apr 9, 2016 at 0:37

answered Apr 9, 2016 at 0:31

user4227915

Comments

George Chen · Accepted Answer · 2016-04-09 00:42:21Z

0

var parseString = function(n) { 
    return n.split('')
          .reduce(function(a, b) {
                  return parseInt(a) + parseInt(b);
           })
    };

myArr.map(function(str) {return   parseString(str)})

edited Apr 9, 2016 at 0:42

answered Apr 9, 2016 at 0:36

George Chen

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1 Comment

Huey Over a year ago

Do make sure you add an explanation to help people better understand your answer, rather than just leaving a chunk of code.

Jason · Accepted Answer · 2016-04-09 00:58:28Z

0

I think this fiddle gives you the result you are after:

var myArr = [ "111" , "222" , "333" ] ;
var newArr = myArr.map(function(string){
    var chars = string.split("")
  var value = 0;
  for(var i = 0; i < chars.length; i++ ){
    value = value + parseInt(chars[i])
  }
  return value;
})

https://jsfiddle.net/bw7s6yey/

answered Apr 9, 2016 at 0:58

Jason

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Comments

Andy · Accepted Answer · 2016-04-09 03:29:41Z

0

An ES6 approach in two lines.

const sum = (arr) => arr.reduce((p, c) => +p + +c);
let out = myArr.map(el => sum([...el]));

DEMO

edited Apr 9, 2016 at 3:29

answered Apr 9, 2016 at 0:59

Andy

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1 Comment

user4227915 Over a year ago

ES6 allows you to use [...el] instead of el.split('')

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