Hi, R people. In ?factor, in the "Examples:" section, we see:
## suppose you want "NA" as a level, and to allowing missing values. (x <- factor(c(1, 2, "NA"), exclude = "")) is.na(x)[2] <- TRUE x # [1] 1 <NA> NA, <NA> used because NA is a level. is.na(x) # [1] FALSE TRUE FALSE I'm a bit confused by this example, as I do not understand the point being made. Using 'exclude = ""' or not does not change the outcome. What is being demonstrated by this clause, here? Isn't "NA" a mere string, not really related to a missing value? It might also be some kind of linguistic problem, and I'm not a native English speaker. The "and to allowing" construct sounds strange to me. I would expect either "and to allow" or "and allowing", but maybe I'm plainly missing the meaning of the statement. Could this be clarified somehow? -- François Pinard http://pinard.progiciels-bpi.ca ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
