R converts floats to strings with ~15 digits of accuracy, specifically to avoid differentiating between 1 and 1 + .Machine$double.eps, it is assumed that small differences such as this are due to rounding errors and are unimportant.
So, if when making your factor, you want all digits, you could write this: `as.factor(format(x, digits = 17L))` On Wed, Jan 25, 2023 at 4:03 AM Tobias Fellinger <to...@htu.at> wrote: > > Hello, > > I'm encountering the following error: > > In a package for survival analysis I use a data.frame is created, one column > is created by applying unique on the event times while others are created by > running table on the event times and the treatment arm. > > When there are event times very close together they are put in the same > factor level when coerced to factor while unique outputs both values, leading > to different lengths of the columns. > > Try this to reproduce: > x <- c(1, 1+.Machine$double.eps) > unique(x) > table(x) > > Is there a general best practice to deal with such issues? > > Should calling table on floats be avoided in general? > > What can one use instead? > > One could easily iterate over the unique values and compare all values with > the whole vector but this are N*N comparisons, compared to N*log(N) when > sorting first and taking into account that the vector is sorted. > > I think for my purposes I'll round to a hundredth of a day before calling the > function, but any advice on avoiding this issue an writing more fault > tolerant code is greatly appreciated. > > all the best, Tobias > > > [[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.
