how to split a list of numpy arrays and concatenate arrays of euch sublists in python

I have a list of numpy arrays and want to firstly split the list and then concatenate all the arrays exiting in each sublist. Number of sublists is defined by:

n_sublist=2 # but in reality I have much more sublists

this is my list:

all_data=[np.array([[1., 2., 3.], [10., 11., 12.]]),
          np.array([[5., 3., 1.]]),
          np.array([[2., -1., 11.]]),
          np.array([[4., -2., 31.], [1., 8., 8.]]),
          np.array([[0., 0., 0.]]),
          np.array([[22., 9., 7.]]),
          np.array([[-4., 9., 21.], [5., 0., 0.]]),
          np.array([[4., 1., 2.]])]

The length of all_data is 8 and it should be firstly modified to be a list of n_sublist lists. I mean two sublists which first one has the first four arrays and second one has the last four arrays. Then, all the arrays of each sublist should be concatenated. Finally, I want the following list as output:

final_ls=[[[1., 2., 3.], [10., 11., 12.],
           [5., 3., 1.],
           [2., -1., 11.],
           [4., -2., 31.], [1., 8., 8.]],
          [[0., 0., 0.],
           [22., 9., 7.],
           [-4., 9., 21.], [5., 0., 0.],
           [4., 1., 2.]]]

I tried the following method but I was not successful to do so:

A = all_data[:len(all_data)//n_sublist]
B = all_data[len(all_data)//n_sublist:]
A=[l.tolist() for l in A]
B=[l.tolist() for l in B]
final_ls=[A,B]

Answer

You can do:

n = len(all_data)//n_sublist
final_lst = [np.concatenate(all_data[:n]).tolist(), 
             np.concatenate(all_data[n:]).tolist() ]

Output:

[[[1.0, 2.0, 3.0],
  [10.0, 11.0, 12.0],
  [5.0, 3.0, 1.0],
  [2.0, -1.0, 11.0],
  [4.0, -2.0, 31.0],
  [1.0, 8.0, 8.0]],
 [[0.0, 0.0, 0.0],
  [22.0, 9.0, 7.0],
  [-4.0, 9.0, 21.0],
  [5.0, 0.0, 0.0],
  [4.0, 1.0, 2.0]]]

Note for general number n_sublist:

final_lst = [np.concatenate(all_data[i*n:i*n+n]).tolist()
             for i in range(n_sublist)]