Without knowing more about your data, it is hard to say for certain, but might you be confusing unique _values_ with _factor levels_?
> mydata <- as.factor(sort(rep(1:5, 2))) # mydata has 10 values, 5 unique values, and 5 factor levels > mydata [1] 1 1 2 2 3 3 4 4 5 5 Levels: 1 2 3 4 5 > unique(mydata) [1] 1 2 3 4 5 Levels: 1 2 3 4 5 > mydata.subset <- mydata[1:4] # the subset now has only 2 unique values, but the output # still lists all five factor levels > unique(mydata.subset) [1] 1 2 Levels: 1 2 3 4 5 # try drop=TRUE as an option to subset > mydata.subset <- mydata[1:4, drop=TRUE] > unique(mydata.subset) [1] 1 2 Levels: 1 2 Alternatively, if this is the problem and you don't need those data to be factors, you could always convert them to a more appropriate form. Sarah > > On 1/25/07, lalitha viswanath > > <[EMAIL PROTECTED]> wrote: > > > Hi > > > I am new to R programming and am using subset to > > > extract part of a data as follows > > > > > > names(dataset) = > > > c("genome1","genome2","dist","score"); > > > prunedrelatives <- subset(dataset, score < -5); > > > > > > However when I use unique to find the number of > > unique > > > genomes now present in prunedrelatives I get > > results > > > identical to calling unique(dataset$genome1) > > although > > > subset has eliminated many genomes and records. > > > > > > I would greatly appreciate your input about using > > > "unique" correctly in this regard. > > > > > > Thanks > > > Lalitha > > > -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.