Converting 3d Matrix To Cascaded 2d Matrices

I have a 3D matrix in python as the following: import numpy as np a = np.ones((2,2,3)) a[0,0,0] = 2 a[0,0,1] = 3 a[0,0,2] = 4 I want to convert this 3D matrix to a set of 2D matr

Solution 1:

Use transpose alongwith reshape -

a.transpose([0,2,1]).reshape(a.shape[0],-1)

Or use swapaxes that does the same job as transpose alongwith reshape -

a.swapaxes(2,1).reshape(a.shape[0],-1)

Sample run -

In [66]: a
Out[66]: 
array([[[ 2.,  3.,  4.],
        [ 1.,  1.,  1.]],

       [[ 1.,  1.,  1.],
        [ 1.,  1.,  1.]]])

In [67]: a.transpose([0,2,1]).reshape(a.shape[0],-1)
Out[67]: 
array([[ 2.,  1.,  3.,  1.,  4.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.]])

In [68]: a.swapaxes(2,1).reshape(a.shape[0],-1)
Out[68]: 
array([[ 2.,  1.,  3.,  1.,  4.,  1.],
       [ 1.,  1.,  1.,  1.,  1.,  1.]])