[Numpy-discussion] Masked array fill_value
Eric Firing
efiring at hawaii.edu
Sat Jul 19 17:21:04 EDT 2008
Ryan May wrote:
> Hi,
>
> I just noticed this and found it surprising:
>
> In [8]: from numpy import ma
>
> In [9]: a = ma.array([1,2,3,4],mask=[False,False,True,False],fill_value=0)
>
> In [10]: a
> Out[10]:
> masked_array(data = [1 2 -- 4],
> mask = [False False True False],
> fill_value=0)
>
>
> In [11]: a[2]
> Out[11]:
> masked_array(data = --,
> mask = True,
> fill_value=1e+20)
>
> In [12]: np.__version__
> Out[12]: '1.1.0'
>
> Is there a reason that the fill_value isn't inherited from the parent array?
There was a thread about this a couple months ago, and Pierre GM
explained it. I think the point was that indexing is giving you a new
masked scalar, which is therefore taking the default mask value of the
type. I don't see it as a problem; you can always specify the fill
value explicitly when you need to.
Eric
>
> Ryan
>
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