Hi, Just do the following:
> tran<-c(7.2) > tgrid<-c(7.1,7.4,7.3,7.1,7.3) > tgrid<-tgrid-tran > tgrid [1] -0.1 0.2 0.1 -0.1 0.1 > abs(tgrid[tgrid>0.1]) [1] 0.2 Andrés > El 12/06/2015, a las 11:01, Jeff Newmiller <jdnew...@dcn.davis.ca.us> > escribió: > > FAQ 7.31 > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > Sent from my phone. Please excuse my brevity. > > On June 12, 2015 8:39:48 AM PDT, "Nelson, Gary (MISC)" > <gary.nel...@state.ma.us> wrote: >> I have come across some odd behavior (to me) using the abs() function >> that I wonder if anyone can explain. >> >> Using R version 3.2.0, I created a vector of absolute values using >> the following code: >> >>> tran<-c(7.2) >>> tgrid<-c(7.1,7.4,7.3,7.1,7.3) >>> dgrid<-abs(tgrid-tran) >>> dgrid >> [1] 0.1 0.2 0.1 0.1 0.1 >> >> When I tried to extract just the rows with values>0.1, I get >> >>> dgrid[dgrid>0.1] >> [1] 0.1 0.2 0.1 >> >> There should be only 1 value extracted. >> >> However, if I enter the values by hand >> >>> bgrid<-c(0.1,0.2,0.1,0.1,0.1) >>> bgrid >> [1] 0.1 0.2 0.1 0.1 0.1 >>> bgrid[bgrid>0.1] >> [1] 0.2 >> >> The result is correct. So why is this happening? >> >> I did explore a little bit and found >> >>> as.character(dgrid) >> [1] "0.100000000000001" "0.2" >> [3] "0.0999999999999996" "0.100000000000001" >> [5] "0.0999999999999996" >> >> which shows the absolute values of the negative differences are >> slightly greater than the difference of 0.1 >> >> Is this normal behavior for the abs() function? >> >> Thanks, >> >> Gary Nelson >> >> [[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. ______________________________________________ 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.