How to swap the rows and columns of a matrix in JavaScript

In this Article we will go through how to swap the rows and columns of a matrix only using single line of code in JavaScript. This is a one-line JavaScript code snippet that uses one of the most popular ES6 features => Arrow Function.

Let's define this short function:

const transpose = matrix => matrix[0].map((col, i) => matrix.map(row => row[i]));

#Or

const transpose = matrix => matrix[0].map((col, c) => matrix.map((row, r) => matrix[r][c]));

#Or

const transpose = matrix => matrix.reduce((prev, next) => next.map((item, i) => (prev[i] || []).concat(next[i])), []);

#Example

transpose([             // [
    [1, 2, 3],          //      [1, 4, 7],
    [4, 5, 6],          //      [2, 5, 8],
    [7, 8, 9],          //      [3, 6, 9],
]);                     //  ]
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