Create a sphere with its center (i,j,k) and cuboid (x0,y0,z0):
points_in_sphere = (x0 - i)**2 + (y0 - j)**2 + (z0 - k)**2 <= (radius)**2
Extract the coordinates of the points:
x1,y1,z1 = np.argwhere(points_sphere)[:,0], np.argwhere(points_sphere)[:,1], np.argwhere(points_sphere)[:,2]
Print the point values:
print cubiod[x1,y1,z1]