To rotate 90 degree, select each column from left to right into a new list, reverse the list and append result to output.
matrix = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] output = [] h = len(matrix) w = len(matrix[0]) for i in range(w): c = [] for j in range(h): c.append(matrix[j][i]) output.append(c[::-1]) print(output)
const matrix = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]; const output = []; const h = matrix.length; const w = matrix[0].length; for (let i = 0; i < w ; i++) { let c = []; for (let j = 0; j < h; j++) { c.push(matrix[j][i]); } output.push(c.reverse()); } console.log(output);