Perhaps it is worth pointing out (in case the OP thinks this is SQL) that the special value NA is used for "missing" in R.
y[1] <- NA works just fine. -- Sent from my phone. Please excuse my brevity. On May 24, 2017 11:51:41 AM PDT, Marc Schwartz <[email protected]> wrote: > >> On May 24, 2017, at 1:30 PM, Ramnik Bansal <[email protected]> >wrote: >> >> What is the cause of the error below ? >> >>> y <- 1 >>> y[1] <- NULL >> Error in y[1] <- NULL : replacement has length zero >> >> Thanks, >> Ramnik > >Hi, > >> length(NULL) >[1] 0 > >You are attempting to assign NULL, which is a zero length special >object of its own kind, to a specific element in the vector object 'y' >and that cannot be done. > >You can assign NULL to 'y': > >y <- NULL > >> y >NULL > >> length(y) >[1] 0 > > >BUT, 'y' is not a vector in that case: > >> is.vector(y) >[1] FALSE > > > >Nor can a vector contain multiple NULLs: > >y <- c(NULL, NULL, NULL) > >> y >NULL > >> length(y) >[1] 0 > > > >Similarly: > >y <- c(1, NULL, 1) > >> y >[1] 1 1 > >> length(y) >[1] 2 > > >Perhaps reviewing ?NULL as well as: > >https://cran.r-project.org/doc/manuals/r-release/R-lang.html#NULL-object > >might also provide some insights. > >Regards, > >Marc Schwartz > >______________________________________________ >[email protected] 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. ______________________________________________ [email protected] 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.
