A = [[1, 2, 3],
[4, 5, 6]]
D = [[1,4],
[2,5],
[3,6]]
B = [[1, 2, 3],[4, 5, 6]]
C = []
for i in B:
for j in i:
C.append(j)
print('C = ',C)
m = len(B) # число строк
n = len(B[0]) # число колонок
D = [[0] * m for i in range(n)] # скелет повёрнутой матрицы
C = [1, 2, 3, 4, 5, 6]
D = [[0, 0], [0, 0], [0, 0]]
matrix_t = list(zip(*matrix))