# Stack a list of numpy arrays

I have a list of numpy arrays that are of the following shapes:

`(16, 250, 2) (7, 250, 2) (1, 250, 2) `

I’m trying to stack them all together so they are a single numpy array of shape :

`(24, 250, 2) `

I tried using np.stack but I get the error:

`ValueError: all input arrays must have the same shape `

The trick is to use the right stacking method, in your case since you are stacking vertically you should use np.vstack

`import numpy as np a = np.random.random((16, 250, 2)) b = np.random.random((7, 250, 2)) c = np.random.random((1, 250, 2)) arr = np.vstack((a,b,c)) arr.shape (24, 250, 2) `

You can use np.concatenate: You will get this:-

`a = np.random.rand(16,250,2) b = np.random.rand(7,250,2) c = np.random.rand(1,250,2) print(np.shape(np.concatenate([a,b,c], axis=0)) `

Output:

`(24,250,2) `