Join two 2D numpy array with one row over another-CodePudding

Two numpy arrays, lets say

a = np.array([[1,2], [3,4]])
b = np.array([[5,6], [7,8]])

I would like to combine two arrays into one single array such that the results looks like below array

np.array([[1,2],
          [5,6],
          [3,4],
          [7,8]])

I tried using concatenate, merge function, but cannot able to find pythonic way to solve this. Is there is any in built function to solve my problem.

CodePudding user response：

IIUC, you could stack, swap the axes, and reshape:

np.stack([a,b]).swapaxes(0,1).reshape((-1,2))

Or use np.c_ and reshape:

np.c_[a,b].reshape((-1,2))

Output:

array([[1, 2],
       [5, 6],
       [3, 4],
       [7, 8]])

CodePudding user response：

You can column_stack reshape:

out = np.column_stack((a,b)).reshape(4,2)

Output:

array([[1, 2],
       [5, 6],
       [3, 4],
       [7, 8]])