CODEWITHSUNDEEP
javascriptarrayssum
cherron
cherron

Reputation: 21

How can I sum array index values?

I am new to Javascript and at the moment I'm learning how "arrays" are used.

In my code below I have 12 numbers held by an array variable. Next, the for loop is iterating over the indexes to check which values have 2 or more digits, the while-loop then summarizes the digits (e.g. value '130' at index 8, will be 1+3+0=4).

Final step..and also where I'm stuck:

I need to sum up all the "new" index values and return the result in a variable. With the numbers provided in the code, the result would be '50'.

Anyone have clue on how to do this? I've tried the conventional for-loop with sum += array[i], but it doesn't work.

var arrChars = [4, 2, 14, 9, 0, 8, 2, 4, 130, 65, 0, 1];

for (var i = 0; i < arrChars.length; i++) {
  var digsum = 0;

  while (arrChars[i] > 0) {
    digsum += arrChars[i] % 10;

    arrChars[i] = Math.floor(arrChars[i] / 10);
  }

  var sum = 0; // this last part won't work and I just get "nan", 12 times

  for (var j = 0; j < arrChars.length; j++) {
    sum += parseInt(digsum[j]);
  }

  console.log(sum); // desired output should be '50'
}

Upvotes: 0

Views: 540

Answers (2)

Heretic Monkey
Heretic Monkey

Reputation: 12113

I'd make this easy and just flatten the array of numbers into a string of digits, split that into an array of single digits, and add them together:

var arrChars = [4, 2, 14, 9, 0, 8, 2, 4, 130, 65, 0, 1];

console.log([...arrChars.join('')].reduce((agg, cur) => agg += +cur, 0));

Upvotes: 1

Irakli Tchedia
Irakli Tchedia

Reputation: 277

Move digsum outside and it will contain the sum of every number in it:

var arrChars = [4, 2, 14, 9, 0, 8, 2, 4, 130, 65, 0, 1];

var digsum = 0;
for (var i = 0; i < arrChars.length; i++) {

  while (arrChars[i] > 0) {
    digsum += arrChars[i] % 10;

    arrChars[i] = Math.floor(arrChars[i] / 10);
  }
}
console.log(digsum); // desired output should be '50'

Upvotes: 1

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