[Numpy-discussion] New patch for MA

Michael Sorich michael.sorich at gmail.com
Thu Apr 6 17:41:19 CDT 2006


On 4/7/06, Sasha <ndarray at mac.com> wrote:
>
>
> 2. I am not sure cumprod and cumsum should fill masked elements with 1 and
> 0.  I would think the result should be masked if any prior element along the
> axis being accumulated is masked.  To ignore masked elements, filled can be
> called explicitly before cum[prod|sum].  One of the problems with filling by
> default is that 1 or 0 are not appropriate values for object arrays (for
> example, "" is an appropriate fill value for cumsum of an array of strings).
>
>
There are often a number of options for how masked values can be dealt with.
In general (not just with cum*), I would prefer for the result to be masked
when masked values are involved unless I explicitly indicate what should be
done with the masked values. Otherwise it is too easy to forget that some
default maniputlation of masked values has been applied. In R there is
commonly an na.action or na.rm parameter to functions.

Michael
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