methods on missing data

Hello everybody!

I have 2 >issues< concerning methods applied to missing data.
I think they're bugs, but who knows.

1. var(NA) returns

     Error in var(NA) : missing observations in cov/cor

instead of NA. I expanded the summary-function to my.summary
including SDev, in order to use it with tapply, which crashes
in case of groups with no valid data.

var() already has a na.rm option that does what you want
R> var(NA,na.rm=TRUE)
[1] NA

2. is a similar problem. I use tapply with hist. On groups
without valid data it crashes, like hist(as.numeric(c(NA)))
returning

     Error in pretty(rx, n = nnb, min.n = 1) : x must be numeric

hist(as.numeric(c(NA)),breaks=c(1,2)) works, as it does not use "pretty".

I know these are very special cases, but unfortunately they kill the whole
process.

try() is a general solution to the problem of functions that must
sometimes be applied to invalid data without causing an error.  Unlike the
var(NA) case, hist(NA) can't really do anything useful so try() is a
reasonable solution.

	-thomas

Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
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
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._