Hi Ramnik, Bert's answer is correct, and an easy way to see why is to look at:
c(1,F,"b") [1] "1" "FALSE" "b" The reason that "F" is translated to "FALSE" is that is its default value when R is started. If you change that value: F<-"foo" c(1,F,"b") [1] "1" "foo" "b" as.logical(c(1,F,"b")) [1] NA NA NA To find out why as.numeric warns you and as.logical doesn't, we will have to await the response of someone who knows. I suspect that as.numeric employs a fairly sophisticated analysis of a string to see if it is a number while as.logical just shoves the value (x) into a conditional like: x != 0 Jim On Tue, Nov 22, 2016 at 2:57 AM, Bert Gunter <bgunter.4...@gmail.com> wrote: > Not an answer, but note that your vectors are all first (silently) > coerced to character, as vectors must be all of one type. > > I would hazard a guess that the answer is: it's simply an arbitrary > inconsistency (different folks wrote the functions at different > times). Note that AFAICS, the difference has no effect on the behavior > of the two functions, i.e. the behavior is consistent, which is what > counts. However, I of course defer to real experts. > > -- Bert > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Mon, Nov 21, 2016 at 1:52 AM, Ramnik Bansal <ramnik.ban...@gmail.com> > wrote: >> Hi, >> >> I am trying to understand under which specific conditions does explicit >> coercion produce warnings. >> >>> as.numeric(c(1, F, "b")) >> [1] 1 NA NA >> Warning message: >> NAs introduced by coercion >> >>> as.logical(c(1, F, "b")) >> [1] NA FALSE NA >> >> >> In above examples, as.numeric produces warning but as.logical does not. >> What is the reason behind this different behaviour. Ideally as.logical >> should also have produced the warning message like as.numeric. >> >> Thanks in advance. >> Ramnik >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
