[R] missing values

[Ulrich Leopold]

Dear list,

how can I exclude the missing values in the following example:

tapply(lsk0t50$Pox2, lsk0t50$ProfN, sum)

I tried:

tapply(lsk0t50$Pox2, lsk0t50$ProfN, sum, Fun=is.na(lsk0t50$Pox2))

But it returns a lot of missing values in the result. Instead the missing 
values in the variable should not be taken into account. So that I get only 
a NA as result if there are only NAs for the corresponding factor.

Any idea how this can be achieved?

Thanks,
Ulrich
-- 
__________________________________________________

Ulrich Leopold MSc.

Department of Physical Geography
Institute for Biodiversity and Ecosystem Dynamics
Faculty of Science
University of Amsterdam
Nieuwe Achtergracht 166
NL-1018WV Amsterdam

Phone: +31-(0)20-525-7456 (7451 Secretary)
Fax:   +31-(0)20-525-7431
Email: uleopold at science.uva.nl
http://www.frw.uva.nl/soil/Welcome.html

Check us also out at:
Netherlands Centre for Geo-ecological Research
http://www.frw.uva.nl/icg



-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._