Hi Or you could use rounding. which(round(lut, 3)==1.8) [1] 401
Cheers Petr > -----Original Message----- > From: R-help <r-help-boun...@r-project.org> On Behalf Of Ben Tupper > Sent: Thursday, January 17, 2019 2:43 PM > To: POLWART, Calum (COUNTY DURHAM AND DARLINGTON NHS > FOUNDATION TRUST) <calum.polw...@nhs.net> > Cc: r-help@r-project.org > Subject: Re: [R] I can't get seq to behave how I think it should > > 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. Osobní údaje: Informace o zpracování a ochraně osobních údajů obchodních partnerů PRECHEZA a.s. jsou zveřejněny na: https://www.precheza.cz/zasady-ochrany-osobnich-udaju/ | Information about processing and protection of business partner’s personal data are available on website: https://www.precheza.cz/en/personal-data-protection-principles/ Důvěrnost: Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a podléhají tomuto právně závaznému prohláąení o vyloučení odpovědnosti: https://www.precheza.cz/01-dovetek/ | This email and any documents attached to it may be confidential and are subject to the legally binding disclaimer: https://www.precheza.cz/en/01-disclaimer/ ______________________________________________ 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.
