行列の転置と90°回転

行列$A$の転置と90°回転を求める。

A = \begin{bmatrix}
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9
\end{bmatrix}

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

90°回転

結論

rotate = lambda A: [list(x)[::-1] for x in zip(*A)] 

rotate(A) # [[7, 4, 1], [8, 5, 2], [9, 6, 3]]

転置

結論

transpose = lambda A: [list(x) for x in zip(*A)]

transpose(A) # [[1, 4, 7], [2, 5, 8], [3, 6, 9]]

結論

zipは便利