[Numpy-discussion] saving groups of numpy arrays to disk
Paul Anton Letnes
Fri Aug 26 04:22:56 CDT 2011
On 25. aug. 2011, at 23.49, David Warde-Farley wrote:
> On 2011-08-25, at 2:42 PM, Chris.Barker wrote:
>> On 8/24/11 9:22 AM, Anthony Scopatz wrote:
>>> You can use Python pickling, if you do *not* have a requirement for:
>> I can't recall why, but it seem pickling of numpy arrays has been
>> fragile and not very performant.
>> I like the npy / npz format, built in to numpy, if you don't need:
>>> - access from non-Python programs
> While I'm not aware of reader implementations for any other language, NPY is a dirt-simple and well-documented format designed by Robert Kern, and should be readable without too much trouble from any language that supports binary I/O. The full spec is at
> It should be especially trivial to read arrays of simple scalar numeric dtypes, but reading compound dtypes is also doable.
> For NPZ, use a standard zip file reading library to access individual files in the archive, which are in .npy format (or just unzip it by hand first -- it's a normal .zip file with a special extension).
Out of curiosity: is the .npy format guaranteed to be independent of architecture (endianness and similar issues)?
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