Numpy 1.3 In [1]: import numpy as np In [2]: a = np.zeros(5).fill(5) In [3]: a In [4]: type(a) Out[4]: <type 'NoneType'> In [5]: a = np.zeros(5) In [6]: a.fill(5) In [7]: a Out[7]: array([ 5., 5., 5., 5., 5.]) What i'm trying to do may not be the best way, but I think it should still have worked. Thoughts? Cheers, Chris