Hi Istvan, That's most unusual, and quite unlikely (and much larger than the usual floating-point rounding errors).
Please provide a reproducible example. I assume you got the data from here: http://www.itl.nist.gov/div898/strd/anova/SmLs07.dat What did you do with it then? How did you delete the header rows? What R code did you use to read it in? What OS and version of R are you working with? R has been well-validated; it's more likely that you did something sub-optimal while importing the data. Sarah On Fri, May 4, 2012 at 9:54 AM, Istvan Nemeth <furgeu...@gmail.com> wrote: > Dear Users! > > I encountered with some problem in data reading while I challenged R (and > me too) in a validation point of view. > In this issue, I tried to utilize some reference datasets ( > http://www.itl.nist.gov/div898/strd/index.html). > And the result departed a bit from my expectations. This dataset dedicated > to challenge cancellation and accumulation errors (case SmLs07), that's why > this uncommon look of txt file. > > Treatment Response > 1 1000000000000.4 > 1 1000000000000.3 > 1 1000000000000.5 > ...... > 2 1000000000000.2 > 2 1000000000000.4 > ..... > 3 1000000000000.4 > 3 1000000000000.6 > 3 1000000000000.4 > ......... > then after a read.table() I expect the same set instead I've got this: > > Treatment Response > 1 1 1000000000000.4000244 > 2 1 1000000000000.3000488 > 3 1 1000000000000.5000000 > ......... > 22 2 1000000000000.3000488 > 23 2 1000000000000.1999512 > 24 2 1000000000000.4000244 > ....... > 58 3 1000000000000.4000244 > 59 3 1000000000000.5999756 > 60 3 1000000000000.4000244 > 61 3 1000000000000.5999756 > 62 3 1000000000000.4000244 > ...... > a lots of number from the space. I assume that these numbers come from the > binary representation of such a tricky decimal numbers but my question is > how can I avoid this feature of the binary representation? > > Moreover, I wondered that it may raise some question in a regulated > environment. > -- Sarah Goslee http://www.functionaldiversity.org ______________________________________________ R-help@r-project.org mailing list 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.
