您可以使用高级索引：

index = np.array([0,1,2])
matrix = np.array([[1,4,7],[2,5,8],[3,6,9]])

res = matrix[np.arange(matrix.shape[0]), index]
# array([1, 5, 9])

第二次例如，反转索引：

For your second example, reverse your indices:

index = np.array([0,1,1])
matrix = np.array([[1,4,7],[2,5,8],[3,6,9]])

res = matrix[index, np.arange(matrix.shape[1])]
# array([1, 5, 8])