[Numpy-discussion] easy way to collapse the last two dimension of an array?

Sebastian Berg sebastian@sipsolutions....
Mon Jun 3 04:53:27 CDT 2013


On Mon, 2013-06-03 at 10:44 +0200, Chao YUE wrote:
> Dear all,
> 
> I have an array with 4 dim:
> 
> In [24]: dd.shape
> Out[24]: (12, 13, 120, 170)
> 
> I would like to collapse the last two dim for applying np.sum(axis=-1)
> 
If you use Numpy >= 1.7. you can also just use dd.sum(axis=(-1,-2))

- Sebastian


> In [25]: dd.reshape(12,13,-1).shape
> Out[25]: (12, 13, 20400)
> 
> is there a more general way to do this? something like
> In [21]: dd.reshape(*dd.shape[0:2],-1).shape
> ------------------------------------------------------------
>    File "<ipython console>", line 1
> SyntaxError: only named arguments may follow *expression (<ipython
> console>, line 1)
> 
> thanks a lot for any hints,
> 
> cheers,
> 
> Chao
> 
> -- 
> ***********************************************************************************
> Chao YUE
> Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL)
> UMR 1572 CEA-CNRS-UVSQ
> Batiment 712 - Pe 119
> 91191 GIF Sur YVETTE Cedex
> Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16
> 
> ************************************************************************************
> _______________________________________________
> NumPy-Discussion mailing list
> NumPy-Discussion@scipy.org
> http://mail.scipy.org/mailman/listinfo/numpy-discussion




More information about the NumPy-Discussion mailing list