[Numpy-discussion] numpy.ascontiguousarray on byteswapped data !?

Travis Oliphant oliphant.travis at ieee.org
Fri Aug 11 15:02:28 CDT 2006

Sebastian Haase wrote:
> I just found this in  myCVS/numpy/numpy/core/tests/test_numerictypes.py
> <code>
> def normalize_descr(descr):
>     "Normalize a description adding the platform byteorder."
>   return out
> </code>

> Is that what I was talking about !?  It's quite a big animal. 
> Would this be needed "everytime" I want to get a "systembyte-ordered version" 
> of a given type !?

No, I'm not even sure why exactly that was written but it's just in the 
testing code.  I think the email I sent yesterday got lost because I 
sent it CC: numpy-discussion with no To: address.

Here's what I said (more or less) in that email:

You can use the .newbyteorder(endian='s') method of the dtype object to 
get a new data-type with a different byteorder.  The possibilities for 
endian are 'swap', 'big' ('>'), 'little' ('<'), or 'native' ('='). 

This will descend down a complicated data-type and change all the 
byte-orders appropriately.

Then you can use .astype(newtype) to convert to the new byteorder.

The .isnative attribute of the data-type will tell you if the data-type 
(or all of it's fields in recent SVN) are in native byte-order.


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