Question

How to transpose a matrix (swap rows and columns) in Rust

Answer 1

fn transpose<T: Copy>(matrix: &Vec<Vec<T>>) -> Vec<Vec<T>> {
    let rows = matrix.len();
    let cols = matrix[0].len();

    let mut result = vec![vec![matrix[0][0]; rows]; cols];

    for i in 0..rows {
        for j in 0..cols {
            result[j][i] = matrix[i][j];
        }
    }

    result
}

fn print_matrix<T: std::fmt::Display>(matrix: &Vec<Vec<T>>) {
    for row in matrix {
        for val in row {
            print!("{} ", val);
        }
        println!();
    }
}

fn main() {
    let matrix = vec![
        vec![1, 2, 3],
        vec![4, 5, 6],
        vec![7, 8, 9],
    ];

    let t = transpose(&matrix);
    print_matrix(&t);
}



/*
run:

1 4 7 
2 5 8 
3 6 9 

*/

 

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