FreeCodeCamp Daily Challenge Solution 5/9/2026

Riley Underwood

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May 16, 2026

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Transposed Matrix (JavaScript)

Given a matrix (an array of arrays), return the transposed version of it.

To transpose the matrix, swap the rows and columns. E.g: a value at index [0, 1] should move to index [1, 0].

For example, given:

[
  [1, 2, 3],
  [4, 5, 6]
]

Return:

[
  [1, 4],
  [2, 5],
  [3, 6]
]

My Solution (JS):

function transpose(matrix) {
  console.log(matrix)
  let transposedMatrix = []
  // Given that each subarray in a matrix should always be the same length. repeat process for the length of the first subarray of the matrix.
  for (let i = 0; i < matrix[0].length; i++) {
    // Empty the row array every loop and add the nth element of the subarray for each iteration.
    let row = []
    // Each time the for loop repeats, the next element of each subarray in the forEach loop will be added.
    matrix.forEach((subArr) => {
      row.push(subArr[i])
    })
    transposedMatrix.push(row)
  }
  
  console.log(transposedMatrix)
  return transposedMatrix;
}

If you have a different solution or an improvement to this one please feel free to comment with your ideas!

See all the solutions I’ve done for these practice problems: https://github.com/BoltenBeeper/FreeCodeCamp-Daily-Coding-Practice-Solutions

Note: I do not use LLMs or AI assistance to write my code. Feel free to use this solution to learn or improve.

Dave Cross also has a great solution on YouTube: https://www.youtube.com/@dave-cross

If you want to see more of me: boltenbeeper.github.io/portfolio