我正在尝试从 Python 3 中的 2D 列表转换 3D 列表

Question

I could not find anything that works for the type of list I am trying to convert. The 2d list is

[[2,3,4],[5,6,7],[8,9,10],[11,12,13]]

and i need a list like

[[[2,3,4],[5,6,7]],[[8,9,10],[11,12,13]]]

I have tried all of these but it does not work. I know the size of the list that I want to convert.

a = np.array(item).reshape(3, round(len(item)/2),round(len(item)/2))
a = np.reshape(np.array(item), (round(len(item)/2), round(len(item)/2), 3))
a = np.array(item)[round(len(item)/2), round(len(item)/2), newaxis]

Answer 1

How about first casting your list to arrays and find out the shapes you wanted and then reshaping accordingly ?

In [2]: lol = [[2,3,4],[5,6,7],[8,9,10],[11,12,13]] 
In [3]: lol_arr = np.array(lol)    

In [4]: lol3 = [[[2,3,4],[5,6,7]],[[8,9,10],[11,12,13]]]
In [5]: lol3_arr = np.array(lol3) 

In [6]: lol_arr.shape                  
Out[6]: (4, 3)

In [7]: lol3_arr.shape                             
Out[7]: (2, 2, 3)

# reshape accordingly
In [9]: np.reshape(lol_arr, (2, 2, 3))                                 
Out[9]: 
array([[[ 2,  3,  4],
        [ 5,  6,  7]],

       [[ 8,  9, 10],
        [11, 12, 13]]])

In [10]: np.reshape(lol_arr, (2, 2, 3)).tolist() 
Out[10]: [[[2, 3, 4], [5, 6, 7]], [[8, 9, 10], [11, 12, 13]]]

# or get the array shape directly
In [11]: np.reshape(lol_arr, lol3_arr.shape).tolist() 
Out[11]: [[[2, 3, 4], [5, 6, 7]], [[8, 9, 10], [11, 12, 13]]]