JAVASCRIPT ) 전치행렬

let a = [
    [1,2,3],
    [4,5,6],
    [7,8,9]
]

let b = a.map((i)=>[...i]);

for(let i=0; i<a.length; i++){
    for(let j=0; j<a[0].length; j++){
        b[i][j] = a[j][i];
    }
}

console.log(a);
console.log(b);