Matrix Addition & Substraction

Part of the Logic & Flow section of Coddy's JavaScript journey — lesson 10 of 65.

To add or subtract two matrices, they must have the same dimensions (i.e., the same number of rows and columns). The operation is performed element-wise, meaning you add or subtract corresponding elements in each matrix.

For example:

Matrix A:
1 2
3 4

Matrix B:
5 6
7 8

A + B:
(1+5) (2+6)
(3+7) (4+8)

Result:
6  8
10 12

Matrix multiplication is more complex and it will be covered in a later section.

Challenge

Easy

Create a function named combineMatrices that takes three arguments: matrixA, matrixB, and a string op which can be either "+" or "-". For each cell, if op is "+", the result should be matrixA[r][c] + matrixB[r][c]. Otherwise, if op is "-", the result should be matrixA[r][c] - matrixB[r][c].

Cheat sheet

Matrix addition and subtraction require matrices with the same dimensions. Operations are performed element-wise on corresponding elements.

Example of matrix addition:

Matrix A:
1 2
3 4

Matrix B:
5 6
7 8

A + B:
(1+5) (2+6)
(3+7) (4+8)

Result:
6  8
10 12

Try it yourself

function combineMatrices(matrixA, matrixB, op) {
  // TODO: For each cell, if op is '+', add the corresponding cells.
  // Otherwise, subtract them. Return the resulting 2D array.
}
// Do not write anything outside function