[Numpy-discussion] Questions about masked arrays

Pierre GM pgmdevlist@gmail....
Tue Oct 6 22:15:40 CDT 2009


On Oct 6, 2009, at 10:58 PM, Gökhan Sever wrote:
>
> I see your points. I don't want to give you extra work, don't  
> worry :) It just seem a bit bizarre:
>
> I[27]: c.data['Air_Temp'].fill_value
> O[27]: 999999.99990000005
>
> I[28]: c.data['Air_Temp'][4].fill_value
> O[28]: 1e+20
>
> As you see, it just returns two different fill_values.

I know, but I hope you see the difference : in the first line, you  
access the `fill_value` of the array. In the second, you access the  
`fill_value` of the `masked` constant. Each time you access a masked  
element of an array with __getitem__, you get the masked constant. We  
could force the constant to inherit the fill_value of the array that  
calls __getitem__, but it'd be propagated.

> I know eventually you will be the one handling this :) it might be  
> good to add this issue to the tracker.

Go for it, but don't expect anything before the release of 1.4.0 (in  
the next few months)

>
> > This is the last resort. I will eventually try this if I don't any
> > other options left.
>
> I gonna have difficulties fixing something that I don't see broken...
> Now, there might be something wrong in my installation. I gonna try to
> install 1.3.0 somwehere. say, what Python are you using ?
>
> OK, I use meld to diff my copy of ma/core.py with the latest trunk  
> version. There are lots of differences :) So there is a possibility  
> that I might have built my local numpy before 09/08. I should renew  
> my copy. Do you know the link of svn browser for the numpy? I don't  
> know how you are making separate installations without overriding  
> other package? I either use Sage (if I have extra time) or SPD. They  
> are both shipped with numpy 1.3.0.

Make yourself a favor and install virtualenv and virtualenvwrapper.  
That way, several versions of the same package can coexist without  
interference. Oh, and install pip till you're at it:

http://pypi.python.org/pypi/virtualenv
http://www.doughellmann.com/projects/virtualenvwrapper/
http://pypi.python.org/pypi/pip







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