[R] Inexplicably different results using subset vs bracket notation on logical variable

[Peter Ehlers]

On 2012-08-28 07:44, Mauricio Cornejo wrote:
> William, David, and Peter,
>
>
> Thank you all so much for your help on this.  Though I had read the help files on 'subset' and '[', I had not been able to discern from that text what the problem was.  I could not have solved it without your help.
>
>
> The help file on 'subset' mentions "For ordinary vectors, the result is simply x[subset & !is.na(subset)]."  However, since I was dealing with a data frame at the time, I failed to appreciate the relevance (but I get it now).
>
>
> I've gone back to read the help on '[' and I still don't see where this functionality is described.  The page has section titled "NAs in indexing", whose content I interpret as being limited to NAs in the indices (and not in the returned values).  I can't find any text in the documentation describing the subtle behavior you kindly pointed out.

Hmmm, it seems to me that the page is clear:

   "... NA index picks an unknown element and so *returns* NA
    in the corresponding element of ..."

(my emphasis)

Isn't that exactly what occurs?

Peter Ehlers

>
> Thanks again,
> Mauricio
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