[R] Problem accessing "row number" from subset on a dataframe

[Jason Rupert]

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 <mark at wardle.org> wrote:

> From: Mark Wardle <mark at wardle.org>
> Subject: Re: [R] Problem accessing "row number" from subset on a dataframe
> To: "Jason Rupert" <jasonkrupert at yahoo.com>
> Cc: R-help at 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 <jasonkrupert at 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 at 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
>