[Numpy-discussion] MA.zeros problem

Reggie Dugard reggie at merfinllc.com
Mon Aug 23 10:27:38 CDT 2004


Stephen,

You might try something like:

>>> a = MA.zeros((2,2))
>>> a
array(
 [[0,0,]
 [0,0,]])
>>> a[1,1] = 2
>>> a
array(
 [[0,0,]
 [0,2,]])

Because MA uses copy semantics, when you specify a[1][1], the a[1] makes
a copy of the first row of the original array, and then the second [1]
index does a setitem on that.  If you use the a[1,1] syntax, the setitem
is done on 'a' itself.

Hope this is of some help.

Reggie Dugard
Merfin, LLC


On Mon, 2004-08-23 at 09:25, smpitts at ou.edu wrote:
> Hi all,
> I have some code that uses Numeric, and I'm trying to change it so that it supports MA as well. My code uses Numeric.zeros to create a matrix and then populates it, but I'm having trouble figuring out how to do something similar in MA.
> 
> Python 2.2.3 (#1, Oct 15 2003, 23:33:35) 
> [GCC 3.3.1 20030930 (Red Hat Linux 3.3.1-6)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import MA
> >>> MA.__version__
> '11.1.0'
> >>> a = MA.zeros((2,2))
> >>> a
> array(
>  [[0,0,]
>  [0,0,]])
> >>> a[1][1] = 2
> >>> a
> array(
>  [[0,0,]
>  [0,0,]])
> 
> Is there some function to automatically create a masked array of arbitrary dimensions filled with zeroes? Thanks.
> --
> Stephen Pitts
> smpitts at ou.edu 
> 
> 
> 
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