Re: Non-contaminating emptyness indicator

[Michael D. Godfrey]

On 07/06/2013 11:54 AM, CdeMills wrote:
> Hello,
>
> I have an application producing lots of data, collating everything into a
> matrix. Sometimes one entry is missing: I would like to fill it with
> something preserving the ability for statistical functions to return
> something meaningfull.
>
> For instance:
> A = randn(4, 4)
> A(2, 3) = NA;
> mean(A) => the third column result is 'NA'
>
> Same game for 'NaN'; furthermore
> A(2, 3) = [] is rejected.
>
> What I would like is some option like R 'skipNA = true', meaning:
> - compute sum, mean, std, ... over some dimension, by default on a
> column-basis
> - extract a slice, and do not take into account NA and NaN values. For
> 'sum', the end result is a numeric value; provided at least one value is not
> special; for operations like 'mean' and 'std' the degrees of freedom have to
> be recomputed each time at least one NA/NaN is present.
>
> Any clue ? Could this option be implemented into the standard implementation
> ? I would like not to implement a new class where NaN are automatically
> discarded ?
>
> Regards
>
> Pascal
This is worth thinking about.  Does anyone know how or if R handles this?
R is the gold standard for statistical computation.  Therefore, some bits of
compatibility with R would be helpful.

Michael