Easy question that I can't find an answer for. I'm trying to subset a data frame and want to exclude the positive values, i.e. I want the NA values. My data:> summary(temp$tuna)Min. 1st Qu. Median Mean 3rd Qu. Max. NA's 1 2 3 3 4 5 1211 Querying for subset(temp, tuna %in% "NA", select.... subset(temp, tuna == NA, select.... subset(temp, tuna == as.character(NA), select.... All yield an empty data frame. An R-help post (http://www.r-project.org/nocvs/mail/r-help/2002/3645.html) suggested looking at http://developer.r-project.org/150update.txt, which I did but I'm confused as to how to accurately query for an NA string. -- Rob Schick Ecologist NOAA Fisheries Santa Cruz Lab 110 Shaffer Road Santa Cruz, CA 95060 Phone: 831.420.3960
> Easy question that I can't find an answer for. I'm trying to subset a > data frame and want to exclude the positive values, i.e. I want the NA > values. > > My data: > > summary(temp$tuna) > Min. 1st Qu. Median Mean 3rd Qu. Max. NA's > 1 2 3 3 4 5 1211 > > Querying for > subset(temp, tuna %in% "NA", select.... > subset(temp, tuna == NA, select.... > subset(temp, tuna == as.character(NA), select.... > > All yield an empty data frame. > > An R-help post > (http://www.r-project.org/nocvs/mail/r-help/2002/3645.html) suggested > looking at http://developer.r-project.org/150update.txt, which I did > but I'm confused as to how to accurately query for an NA string.subset (temp, is.na (temp$tuna), ...)
If `temp' is your data frame and `tuna' is a variable in `temp', then try subset(temp, is.na(tuna)) -roger _______________________________ UCLA Department of Statistics rpeng at stat.ucla.edu http://www.stat.ucla.edu/~rpeng On Wed, 19 Feb 2003, Robert Schick wrote:> Easy question that I can't find an answer for. I'm trying to subset a > data frame and want to exclude the positive values, i.e. I want the NA > values. > > My data: > > summary(temp$tuna) > Min. 1st Qu. Median Mean 3rd Qu. Max. NA's > 1 2 3 3 4 5 1211 > > Querying for > subset(temp, tuna %in% "NA", select.... > subset(temp, tuna == NA, select.... > subset(temp, tuna == as.character(NA), select.... > > All yield an empty data frame. > > An R-help post > (http://www.r-project.org/nocvs/mail/r-help/2002/3645.html) suggested > looking at http://developer.r-project.org/150update.txt, which I did > but I'm confused as to how to accurately query for an NA string. > > > -- > Rob Schick > Ecologist > NOAA Fisheries > Santa Cruz Lab > 110 Shaffer Road > Santa Cruz, CA 95060 > Phone: 831.420.3960 > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-help >