Appending two arrays of same dimensions

Question

I have this array:

array([[[10],
        [20],
        [30]],

       [[20],
        [30],
        [40]]])

And this array:

array([[[110],
        [120],
        [130]]])

Both are 3d array where the dimensions are (2,3,1) and (1,3,1) respectively. I am trying to append the second array to the end of the first array, maintaining its as a 2d array as it seems. So that I would get this

array([[[10],
        [20],
        [30]],

       [[20],
        [30],
        [40]],

       [[110],
        [120],
        [130]]])

What I'm doing is this:

X = np.append(X[:,:,:],a[0])

but all I'm getting back is 1d array : array([ 10, 20, 30, 20, 30, 40, 110, 120, 130]) . This isn't what I want, any idea how to go about it? Thank you for reading.

Answer 1

Another way would be using vstack:

np.vstack((a, b))

[[[ 10]
  [ 20]
  [ 30]]

 [[ 20]
  [ 30]
  [ 40]]

 [[110]
  [120]
  [130]]]

Answer 2

Use np.concatenate:

In [214]: a = np.array([[[10], 
     ...:         [20], 
     ...:         [30]], 
     ...:  
     ...:        [[20], 
     ...:         [30], 
     ...:         [40]]])                                                                                                                                                                                   

In [215]: b = np.array([[[110], 
     ...:         [120], 
     ...:         [130]]])                                                                                                                                                                                  

In [216]: np.concatenate((a, b))                                                                                                                                                                            
Out[216]: 
array([[[ 10],
        [ 20],
        [ 30]],

       [[ 20],
        [ 30],
        [ 40]],

       [[110],
        [120],
        [130]]])