如何求和数组索引值？

Question

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 (eg 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' }

Answer 1

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'

Answer 2

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));

Answer 3

digsum is a number but you're trying to access it as an array ( digsum[j] ). You probably want to overwrite the array with digsum 's value for each index, eg after the while block: arrChars[i] = digsum;