Bert, thanks... The values should not repeat themselves if the same a is closest to all b, so probably aruns example extended with a unique command works best?
unique(a[sapply(b,function(x) which.min(abs(x-a)))]) thanks, Andras --- On Tue, 6/18/13, Bert Gunter <gunter.ber...@gene.com> wrote: > From: Bert Gunter <gunter.ber...@gene.com> > Subject: Re: [R] find closest value in a vector based on another vector values > To: "Jorge I Velez" <jorgeivanve...@gmail.com> > Cc: "Andras Farkas" <motyoc...@yahoo.com>, "R mailing list" > <r-help@r-project.org> > Date: Tuesday, June 18, 2013, 10:07 AM > Jorge: No. > > > a <-c(1,5,8,15,32,33.5,69) > > b <-c(8.5,33) > > a[findInterval(b, a)] > [1] 8 32 ##should be > 8 33.5 > > I believe it has to be done explicitly by finding all the > differences > and choosing those n with minimum values, depending on what > n you > want. > > Note that the problem is incompletely specified. What if the > same > value of a is closest to several values of b? -- do you want > all the > values you choose to be different or not, in which case they > may not > be minimum? > > a <- c(1, 8, 9) > b <- c(2,3) > > Then what are the 2 closest values of a to b? > > -- Bert > > On Tue, Jun 18, 2013 at 5:43 AM, Jorge I Velez <jorgeivanve...@gmail.com> > wrote: > > Dear Andras, > > > > Try > > > >> a[findInterval(b, a)] > > [1] 8 32 > > > > HTH, > > Jorge.- > > > > > > On Tue, Jun 18, 2013 at 10:34 PM, Andras Farkas <motyoc...@yahoo.com> > wrote: > > > >> Dear All, > >> > >> would you please provide your thoughts on the > following: > >> let us say I have: > >> > >> a <-c(1,5,8,15,32,69) > >> b <-c(8.5,33) > >> > >> and I would like to extract from "a" the two values > that are closest to > >> the values in "b", where the length of this vectors > may change but b will > >> allways be shorter than "a". So at the end based on > this example I should > >> have the result "f" as > >> > >> f <-c(8,32) > >> > >> appreciate the help, > >> > >> Andras > >> > >> ______________________________________________ > >> 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. > >> > > > > [[alternative > HTML version deleted]] > > > > ______________________________________________ > > 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. > > > > -- > > Bert Gunter > Genentech Nonclinical Biostatistics > > Internal Contact Info: > Phone: 467-7374 > Website: > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm > ______________________________________________ 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.
