Swap the rows and columns of a matrix

Transpose a rectangular matrix.

JavaScript Version 1.0.0 · MIT · .md

function transpose(matrix) { return matrix[0].map((_, column) => matrix.map(row => row[column])); }

Input & expected output

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

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

The edge case

[
  [
    1
  ]
]

[
  [
    1
  ]
]

Know the limits

• Rows must have the same length; the lab requires a non-empty rectangular matrix.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Clone an array — Create a new array without copying the objects inside it.
• Remove duplicate values — Keep the first occurrence of each value, in its original order.
• Flatten a nested array — Turn a nested array into one sequence of values.