Ok, if you insist [although it's still unclear why you need this level of indirection!]
Try ?which e.g. > which(airquality$Month==5) [1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 > which(airquality$Month==6) [1] 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 > gives the vector indices. These can be used as row indices for the dataframe. bw Mark 2009/5/26 Jason Rupert <jasonkrup...@yahoo.com>: > > Mark, > > I really apprecaite your response and continue to be amazed by the > responsiveness and support on the R forums. > > And, well actually, I would like to get the "row number"(s) and then delete > or not via the row number. > > Again, I really appreciate the response... > > --- On Tue, 5/26/09, Mark Wardle <m...@wardle.org> wrote: > >> From: Mark Wardle <m...@wardle.org> >> Subject: Re: [R] Problem accessing "row number" from subset on a dataframe >> To: "Jason Rupert" <jasonkrup...@yahoo.com> >> Cc: R-help@r-project.org >> Date: Tuesday, May 26, 2009, 3:18 PM >> Hi. I may be missing what you're >> trying to achieve, but... >> >> what about >> >> subset(airquality, airquality$Month!=6) >> >> instead? >> >> You can do arbitrarily complex queries if you wish, >> combining terms logically. >> >> You don't have to use the subset function. You may find it >> helpful to >> see what the following result in: >> >> airquality$Month==6 >> airquality[airquality$Month==6, ] >> airquality[airquality$Month==6, ] >> >> There are ways of getting the row numbers, but I suspect >> you don't >> actually need to do that, do you? >> >> Best wishes, >> >> Mark >> >> 2009/5/26 Jason Rupert <jasonkrup...@yahoo.com>: >> > >> > >> > I would like to use the "row number" information >> returned from performing a subset command on a dataframe. >> > >> > For example, I would like to automatically delete some >> rows from a dataframe if they match a criteria. Here is my >> example below. >> > >> > data(airquality) >> > names(airquality) >> > subset(airquality, airquality$Month == 6) >> > >> > Now how do I delete the row numbers returned >> automatically? >> > >> > I know I can type >> > airquality_mod<-airquality[-c(32:60)] >> > >> > However, I would like to check the row information and >> then use it to delete the stuff out of the dataframe. >> > >> > Thank again for any feedback and insights. >> > >> > ______________________________________________ >> > 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. >> > >> > >> >> >> >> -- >> Dr. Mark Wardle >> Specialist registrar, Neurology >> Cardiff, UK >> > > > > > -- Dr. Mark Wardle Specialist registrar, Neurology Cardiff, UK ______________________________________________ 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.
