I think this is a "Doctor, it hurts when I do this" issue. The root of it is that as.character() behaves differently on integers and floating values.
> factor(100000) [1] 1e+05 Levels: 1e+05 > factor(100000,levels=100000) [1] 1e+05 Levels: 1e+05 > factor(100000,levels=100000:100000) [1] <NA> > factor(as.integer(100000),levels=100000:100000) [1] 100000 Levels: 100000 Or, more directly: It is the difference between these > as.character(seq(99999L,100001L,1L)) [1] "99999" "100000" "100001" > as.character(seq(99999L,100001L,1)) [1] "99999" "1e+05" "100001" in which the formatting code has detected that "1e+05" is shorter than "100000", but won't convert integers to scientific notation. You can play whack-a-mole with this sort of issue: Fix a perceived problem in one place only to find a new problem popping up elsewhere. It is probably better just to never trust character conversion of numbers beyond 99999. - pd > On 23 May 2024, at 18:33 , Andrew Gustar <andrew_gus...@msn.com> wrote: > > This thread on stackoverflow illustrates the problem... > https://stackoverflow.com/questions/78523612/r-factor-from-numeric-vector-drops-every-100-000th-element-from-its-levels > > The issue is that factor(), applied to numeric values, uses as.character(), > which converts numbers to character strings according to the value of scipen. > The stackoverflow thread illustrates a case where this causes some factor > levels to become NA. There is also an inconsistency between the treatment of > numeric and integer values. > > On the face of it, using format(..., scientific = FALSE) instead of > as.character() would solve the problem, but this probably needs careful > thinking through in case of other side effects! > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
