Re: Skipping NA's in statistical functions?

[Søren Hauberg]

son, 08 03 2009 kl. 11:12 +0100, skrev Soren Hauberg:
> For the basic statistical functions ('mean', 'std', ...) this boils down
> to making 'sum' and 'sumsq' skip NA's. For more complicated functions,
> e.g. 'cov', some more work is required. In the thread at the
> Octave-Forge list, Jaroslav and myself proposed an implementation of
> 'cov' that optionally allows NA skipping. The implementation is
> compatible with Matlab, and follows the same strategy as R.

Just a quick follow-up: the 'sum' and 'mean' functions in R do not skip
NA's by default, but have optional arguments that changes this
behaviour. I don't know if R allows

  1 + NA

to ever be evaluated to something different than NA.

Soren