Hi, This looks like a floating point reality bump - see
https://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f <https://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f> You can use other methods to finding your row - I would opt for findInterval() > lut = seq(1.4, 2.1, by=0.001) > findInterval(1.8, lut) [1] 401 findInterval() uses a rapid search to find the index in the look up table (lut) that is just less than or equal to the search value (in your example 1.8). Cheers, Ben > On Jan 17, 2019, at 8:33 AM, POLWART, Calum (COUNTY DURHAM AND DARLINGTON NHS > FOUNDATION TRUST) via R-help <r-help@r-project.org> wrote: > > I am using seq with the expression seq(1.4, 2.1, by=0.001) to create a > sequence of references from 1.4 to 2.1 in 0.001 increments. They appear to > be created correctly. They have a related pair of data which for the > purposes of this we will call val. I'm interested in the content on the row > with seq = 1.8. But I can't seem to get it returned. I can get other values > but not 1.8! yet looking at row 401 there is nothing to indicate an issue > >> a = 1.4 >> b = 2.1 >> seq = seq(a, b, by=0.001) >> val = ceiling(seq * 50) >> s=data.frame(seq, val) >> s$val[seq==1.799] > [1] 90 >> s$val[s$seq==1.8] > numeric(0) >> s$val[seq==1.8] > numeric(0) >> s$val[s$seq==1.800] > numeric(0) >> s$val[s$seq==1.801] > [1] 91 >> head(s[s$seq>1.798,]) > seq val > 400 1.799 90 > 401 1.800 90 > 402 1.801 91 > 403 1.802 91 > 404 1.803 91 > 405 1.804 91 > > > Can anyone explain what's going on here and how I would correctly find the > content of row 401 by using an expression to equal the seq column? > > > > > > ******************************************************************************************************************** > > This message may contain confidential information. If ...{{dropped:25}} ______________________________________________ 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.
