# Swap the rows and columns of a matrix

Transpose a rectangular matrix.

Canonical: https://1loc.dev/array/swap-the-rows-and-columns-of-a-matrix/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

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

## Input

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

## Expected output

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

## Edge case

Input:
```json
[
  [
    1
  ]
]
```
Output:
```json
[
  [
    1
  ]
]
```

## Limits

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

The lab validates types and size before calling this function. Add equivalent validation at your own trust boundary.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/swap-the-rows-and-columns-of-a-matrix.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Validates a non-empty rectangular matrix. Original MDX retained as inert source evidence.