Perhaps a simple questions, but I am using numpy, and iteratively generating 9x9x9 matrices.
I would like to stack these so I end up with Nx9x9x9, but using append, stack and stack it seems to vectorise one of the dimensions rather than add these as individual objects. any ideas how I can do this?
thanks
This could be resolved using np.vstack but to get this in the shape you want to need to add another dimension (an empty one) as first. Otherwise you would stack you current first dimension:
import numpy as np
a = np.ones((1,2,2,2))
print(a.shape) # (1, 2, 2, 2)
or if you create your arrays, then add another dimension by:
a = np.ones((2,2,2))
a = a[None, :] # Adds an dimension as first
and then to stack them you could use:
b = np.vstack([a,a])
print(b.shape) # (2, 2, 2, 2)
c = np.vstack([b,a])
print(c.shape) # (3, 2, 2, 2)
c.shape
you said you create them iterativly but if you only need the final result at the end you don't even need to use vstack just create a new array:
a = np.ones((9,9,9))
b = np.ones((9,9,9))
c = np.ones((9,9,9))
d = np.ones((9,9,9))
res = np.array([a, b, c, d])
print(res.shape) # (4, 9, 9, 9)
np.array([a,b,c,d]) should produce the same thing. np.vstack([i[None,...] for i in [a,b,c,d]]) is another expression.