[Numpy-discussion] Question about np.savez

[jorgesmbox-ml at yahoo.es]

Hi,
I know the documentation states that np.savez saves numpy arrays, so my question relates to misusing it. Before reading the doc in detail, and after reading about pickle and other options to make data persistent, I passed np.savez a list of ndarrays. It didn't complain, but when I loaded the data back, the list had been turned into an ndarray. Is this behaviour expected? It did surprise me. Below  there is an example:

In [18]: l
Out[18]: 
[array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
 array([ 0,  2,  4,  6,  8, 10, 12, 14, 16, 18]),
 array([ 0,  3,  6,  9, 12, 15, 18, 21, 24, 27])]

In [19]: np.savez('test.npz', l=l)

In [20]: data = np.load('test.npz')

In [21]: l1 = data['l']

In [22]: l1
Out[22]: 
array([[ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9],
       [ 0,  2,  4,  6,  8, 10, 12, 14, 16, 18],
       [ 0,  3,  6,  9, 12, 15, 18, 21, 24, 27]])


jorge