Sum of two arrays

[Patric]

Hello

I'm trying to find the sum of two arrays.
but, NaN error occurs.
I think it's because the elements of the array are mixed with characters.

How do I solve this problem?

 

[BigDady]

If you're trying to add the 202309:10 itself you need to do this element by element,

BTW Please use the </> icon above and insert code so we can copy it easily. Pasting a picture doesn't help much.

 

[VBService]

I'm trying to find the sum of two arrays.

what you mean about sum two arrays, you want merge (concatenate), because in javascript + operator you can only use to add numbers or concatenate strings.

e.g.

const array1 = [
  { Name:'James', Subject:'English', 202309:10, 202310:30, 202311:50 },
  { Name:'Neoh',  Subject:'Math'   , 202309:20, 202310:15, 202311:90 }
];

const array2 = [
  { Name:'James', Subject:'English', 202309:10, 202310:30, 202311:50 },
  { Name:'Neoh',  Subject:'Math'   , 202309:20, 202310:15, 202311:90 }
];

const combinedArray1 = array1.concat(array2); //
console.log(combinedArray1);

const combinedArray2 = [...array1, ...array2]; // using the spread operator
console.log(combinedArray2);

or if you want just adding values of 202309:10, 202310:30, 202311:50 for every singel person try use for example a map.

e.g.

const array1 = [
  { Name:'James', Subject:'English', 202309:10, 202310:30, 202311:50 },
  { Name:'Neoh',  Subject:'Math'   , 202309:20, 202310:15, 202311:90 }
];

const array2 = [
  { Name:'James', Subject:'English', 202309:10, 202310:30, 202311:50 },
  { Name:'Neoh',  Subject:'Math'   , 202309:20, 202310:15, 202311:90 }
];

const arraySum = array1.map((item1, index) => {
  const item2 = array2[index];
  return {
    Name: item1.Name,
    Subject: item1.Subject,
    202309: item1[202309] + item2[202309],
    202310: item1[202310] + item2[202310],
    202311: item1[202311] + item2[202311],
  };
});

console.log(arraySum);

like said

to add the 202309:10 itself you need to do this element by element,

 

[VBService]

Here is a more universal algorithm,
[ on-line ]

// Define two arrays with data
const array1 = [
  { Name: 'James', Subject: 'English', 202309: 10, 202310: 30, 202311: 50 },
  { Name: 'Neoh',  Subject: 'Math',    202309: 20, 202310: 15, 202311: 90 },
  { Name: 'Mateo', Subject: 'Chinese', 202310: 20, 202311: 5 }
];

const array2 = [
  { Name: 'James', Subject: 'English', 202309: 10, 202310: 30, 202311: 50 },
  { Name: 'Neoh',  Subject: 'Math',    202309: 20, 202310: 15, 202311: 90 },
  { Name: 'Mateo', Subject: 'Chinese', 202309: 80, 202311: 10 }
];

// Combine the two arrays into one
const combinedArray2 = [...array1, ...array2];
//console.log(combinedArray2);


// Initialize an empty array to store the summed data
const summedArray = combinedArray2.reduce((accumulator, current) => {
  // Check if an existing item with the same Name and Subject exists in the accumulator
  const existingItem = accumulator.find(item => item.Name === current.Name && item.Subject === current.Subject);

  if (existingItem) {
    // If an existing item is found, add the values of fields starting with '2023...'
    for (const key in current) {
      if (!existingItem[key]) existingItem[key] = 0;
      if (key.startsWith('2023')) existingItem[key] += current[key];
    }
  } else {
    // If no existing item is found, add a new entry to the result array
    accumulator.push(current);
  }
  return accumulator;
}, []);

console.log(summedArray);