python - 将 3d 矩阵列表转换为 4d 矩阵

Question

我正在尝试编写一个函数，它接受 3d 矩阵列表..

所以..列表中的每个元素都有形状 (rows,cols, some_scalar). 。 我正在尝试将其 reshape 为 4d 矩阵.. 所以output = (number_of_elements_in_matrix, rows,cols,some_scalar)

到目前为止我有

output = np.zeros((len(list_of_matrices), list_of_matrices[0].shape[0], list_of_matrices[0].shape[1],
                      list_of_matrices[0].shape[2]), dtype=np.uint8)

我怎么知道用值填充这个输出 4d 张量..

def reshape_matrix(list_of_matrices):
   output = np.zeros((len(list_of_matrices), list_of_matrices[0].shape[0], list_of_matrices[0].shape[1],
                          list_of_matrices[0].shape[2]), dtype=np.uint8)


   return output

Answer 1

您可以使用np.stack沿着第一个轴(axis=0)堆叠，就像这样 -

np.stack(list_of_matrices,axis=0)

示例运行 -

In [22]: # Create an input list of arrays
    ...: arr1 = np.random.rand(4,5,2)
    ...: arr2 = np.random.rand(4,5,2)
    ...: arr3 = np.random.rand(4,5,2)
    ...: list_of_matrices = [arr1,arr2,arr3]
    ...: 

In [23]: np.stack(list_of_matrices,axis=0).shape
Out[23]: (3, 4, 5, 2)