array of array sum and breaks when if-condition meet

Question

I have a js array like this.

const test_arr = [ [ 20, 7, 23, 19, 10, 15, 25 ],
 [ 20, 7, 23, 19, 10, 15, 8 ],
  [ 20, 7, 23, 19, 10, 15, 13 ],
  [ 20, 7, 23, 19, 10, 25, 8 ],
  [ 20, 7, 23, 19, 10, 25, 13 ],
  [ 20, 7, 23, 19, 10, 8, 13 ],
  [ 20, 7, 23, 19, 15, 25, 8 ],
  [ 20, 7, 23, 19, 15, 25, 13 ],
  [ 20, 7, 23, 19, 15, 8, 13 ],
  [ 20, 7, 23, 19, 25, 8, 13 ],
  [ 20, 7, 23, 10, 15, 25, 8 ],
  [ 20, 7, 23, 10, 15, 25, 13 ],
  [ 20, 7, 23, 10, 15, 8, 13 ],
  [ 20, 7, 23, 10, 25, 8, 13 ],
  [ 20, 7, 23, 15, 25, 8, 13 ],
  [ 20, 7, 19, 10, 15, 25, 8 ],
  [ 20, 7, 19, 10, 15, 25, 13 ],
  [ 20, 7, 19, 10, 15, 8, 13 ],
  [ 20, 7, 19, 10, 25, 8, 13 ],
  [ 20, 7, 19, 15, 25, 8, 13 ],
  [ 20, 7, 10, 15, 25, 8, 13 ],
  [ 20, 23, 19, 10, 15, 25, 8 ],
  [ 20, 23, 19, 10, 15, 25, 13 ],
  [ 20, 23, 19, 10, 15, 8, 13 ],
  [ 20, 23, 19, 10, 25, 8, 13 ],
  [ 20, 23, 19, 15, 25, 8, 13 ],
  [ 20, 23, 10, 15, 25, 8, 13 ],
  [ 20, 19, 10, 15, 25, 8, 13 ],
  [ 7, 23, 19, 10, 15, 25, 8 ],
  [ 7, 23, 19, 10, 15, 25, 13 ],
  [ 7, 23, 19, 10, 15, 8, 13 ],
  [ 7, 23, 19, 10, 25, 8, 13 ],
  [ 7, 23, 19, 15, 25, 8, 13 ],
  [ 7, 23, 10, 15, 25, 8, 13 ],
  [ 7, 19, 10, 15, 25, 8, 13 ],
  [ 23, 19, 10, 15, 25, 8, 13 ] ]

var combination_before = [ 20,7,23, 19, 10, 15, 25, 8, 13 ]; These are the results of choosing seven out of nine.

I would like to return some elements only when sum of the elements is 100.

how do I make reducer if condition?

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score 2 · Answer 1 · answered Nov 12 '18 at 11:17

you can use filter for filtering your array and reduce for sum your nested arrays, and check in your filter which array sum is equal to 100

const test_arr = [ [ 20, 7, 23, 19, 10, 15, 25 ],
 [ 20, 7, 23, 19, 10, 15, 8 ],
  [ 20, 7, 23, 19, 10, 15, 13 ],
  [ 20, 7, 23, 19, 10, 25, 8 ],
  [ 20, 7, 23, 19, 10, 25, 13 ],
  [ 20, 7, 23, 19, 10, 8, 13 ],
  [ 20, 7, 23, 19, 15, 25, 8 ],
  [ 20, 7, 23, 19, 15, 25, 13 ],
  [ 20, 7, 23, 19, 15, 8, 13 ],
  [ 20, 7, 23, 19, 25, 8, 13 ],
  [ 20, 7, 23, 10, 15, 25, 8 ],
  [ 20, 7, 23, 10, 15, 25, 13 ],
  [ 20, 7, 23, 10, 15, 8, 13 ],
  [ 20, 7, 23, 10, 25, 8, 13 ],
  [ 20, 7, 23, 15, 25, 8, 13 ],
  [ 20, 7, 19, 10, 15, 25, 8 ],
  [ 20, 7, 19, 10, 15, 25, 13 ],
  [ 20, 7, 19, 10, 15, 8, 13 ],
  [ 20, 7, 19, 10, 25, 8, 13 ],
  [ 20, 7, 19, 15, 25, 8, 13 ],
  [ 20, 7, 10, 15, 25, 8, 13 ],
  [ 20, 23, 19, 10, 15, 25, 8 ],
  [ 20, 23, 19, 10, 15, 25, 13 ],
  [ 20, 23, 19, 10, 15, 8, 13 ],
  [ 20, 23, 19, 10, 25, 8, 13 ],
  [ 20, 23, 19, 15, 25, 8, 13 ],
  [ 20, 23, 10, 15, 25, 8, 13 ],
  [ 20, 19, 10, 15, 25, 8, 13 ],
  [ 7, 23, 19, 10, 15, 25, 8 ],
  [ 7, 23, 19, 10, 15, 25, 13 ],
  [ 7, 23, 19, 10, 15, 8, 13 ],
  [ 7, 23, 19, 10, 25, 8, 13 ],
  [ 7, 23, 19, 15, 25, 8, 13 ],
  [ 7, 23, 10, 15, 25, 8, 13 ],
  [ 7, 19, 10, 15, 25, 8, 13 ],
  [ 23, 19, 10, 15, 25, 8, 13 ] ];
  
  const result =  test_arr.filter(arr => arr.reduce((a, b) => a + b, 0) == 100);
  
  console.log(result);

of course but time limit is exists, wait for a second. – horoyoi o Nov 12 '18 at 11:23 — horoyoi o, Nov 12 '18 at 11:23

score 0 · Answer 2 · answered Nov 12 '18 at 11:22

const test_arr = [ [ 20, 7, 23, 19, 10, 15, 25 ],
 [ 20, 7, 23, 19, 10, 15, 8 ],
  [ 20, 7, 23, 19, 10, 15, 13 ],
  [ 20, 7, 23, 19, 10, 25, 8 ],
  [ 20, 7, 23, 19, 10, 25, 13 ],
  [ 20, 7, 23, 19, 10, 8, 13 ],
  [ 20, 7, 23, 19, 15, 25, 8 ],
  [ 20, 7, 23, 19, 15, 25, 13 ],
  [ 20, 7, 23, 19, 15, 8, 13 ],
  [ 20, 7, 23, 19, 25, 8, 13 ],
  [ 20, 7, 23, 10, 15, 25, 8 ],
  [ 20, 7, 23, 10, 15, 25, 13 ],
  [ 20, 7, 23, 10, 15, 8, 13 ],
  [ 20, 7, 23, 10, 25, 8, 13 ],
  [ 20, 7, 23, 15, 25, 8, 13 ],
  [ 20, 7, 19, 10, 15, 25, 8 ],
  [ 20, 7, 19, 10, 15, 25, 13 ],
  [ 20, 7, 19, 10, 15, 8, 13 ],
  [ 20, 7, 19, 10, 25, 8, 13 ],
  [ 20, 7, 19, 15, 25, 8, 13 ],
  [ 20, 7, 10, 15, 25, 8, 13 ],
  [ 20, 23, 19, 10, 15, 25, 8 ],
  [ 20, 23, 19, 10, 15, 25, 13 ],
  [ 20, 23, 19, 10, 15, 8, 13 ],
  [ 20, 23, 19, 10, 25, 8, 13 ],
  [ 20, 23, 19, 15, 25, 8, 13 ],
  [ 20, 23, 10, 15, 25, 8, 13 ],
  [ 20, 19, 10, 15, 25, 8, 13 ],
  [ 7, 23, 19, 10, 15, 25, 8 ],
  [ 7, 23, 19, 10, 15, 25, 13 ],
  [ 7, 23, 19, 10, 15, 8, 13 ],
  [ 7, 23, 19, 10, 25, 8, 13 ],
  [ 7, 23, 19, 15, 25, 8, 13 ],
  [ 7, 23, 10, 15, 25, 8, 13 ],
  [ 7, 19, 10, 15, 25, 8, 13 ],
  [ 23, 19, 10, 15, 25, 8, 13 ] ];
  
  var resultArr = [];
  
  for (var i = 0; i < test_arr.length; i++){
  temp = test_arr[i].reduce(getSum)
    if (temp == 100) {
    resultArr.push(test_arr[i]);
  }
  }
  
  function getSum(total, num) {
    return total + num;
}
  
  
  console.log(resultArr)

Too late, and the use of filter by is Artyom is better! – Wimanicesir Nov 12 '18 at 11:24 — Wimanicesir, Nov 12 '18 at 11:24

score 0 · Answer 3 · answered Nov 12 '18 at 11:59

You could take a different approach at the moment, where you take all combination and return only the ones who match the conditions by length and sum.

function getCombinations(array, length, sum) {
    function iter(array, temp) {
        if (temp.length === length) {
            if (temp.reduce((a, b) => a + b) === sum) {
                result.push(temp);
            }
            return;
        }
        if (!array.length || array.length + temp.length < length) {
            return;
        }
        iter(array.slice(1), temp.concat(array[0]));
        iter(array.slice(1), temp);
    }

    var result = [];    
    iter(array, []);
    return result;
}

var array = [20, 7, 23, 19, 10, 15, 25, 8, 13];

console.log(getCombinations(array, 7, 100));

.as-console-wrapper { max-height: 100% !important; top: 0; }

array of array sum and breaks when if-condition meet

3 Answers3