[R] subsetting a data set

[Sean O'Riordain]

Hi Graham,
Try creating a new column with the two levels that you want...

something along the lines of (warning untested!!!)

GQ1[(GQ1$Status == "Expert) | (GQ1$Status == "Ecol"),]$newColumn <- "AllEcol"
GQ1[GQ1$Status == "Stake",]$newColumn <- "Stake"

and then do the
by(GQ1[,"Max"], list(GQ1$NewColumn), summary)

when in doubt... break the problem into smaller chunks... :-)

cheers,
Sean

On 08/09/06, Graham Smith <myotisone at gmail.com> wrote:
> Petr,
>
> Thanks again, but the data is GQ1, Max is a variable (column)
>
> So I have used
>
>  by(GQ1[,"Max"], list(GQ1$Status), summary)
>
> Which is very good,  and is better than the way I did it before by
> summarising for each status level individually, but that still isn't combing
> the data for Status == "Expert" and Status = "Ecol"
>
> So at the moment the status variable has 3 levels Expert, Ecol and Stake,
>
> I want to analsye that at two levels: Expert and Ecol combined into a new
> level called "AllEcol" and the exsiting level "Stake"
>
> It is this combining the levels that has got me stuck.
>
> Thanks again,
>
> Graham
>
> On 08/09/06, Petr Pikal <petr.pikal at precheza.cz> wrote:
> >
> > Sorry, I did not notice that in your case Max is not a function but
> > your data. So probably
> >
> > by(Max[, your.columns], list(Max$status), summary)
> >
> > is maybe what you want.
> > HTH
> > Petr
> >
> >
> > On 8 Sep 2006 at 10:31, Petr Pikal wrote:
> >
> > From:                   "Petr Pikal" <petr.pikal at precheza.cz>
> > To:                     "Graham Smith" <myotisone at gmail.com>,
> > r-help at stat.math.ethz.ch
> > Date sent:              Fri, 08 Sep 2006 10:31:12 +0200
> > Priority:               normal
> > Subject:                Re: [R] subsetting a data set
> >
> > > Hi
> > >
> > > I am not sure if your Max is the same as max so I am not sure what you
> > > exactly want from your data. However you shall consult ?tapply, ?by,
> > > ?aggregate and maybe also ?"[" together with chapter 2 in intro manual
> > > in docs directory.
> > >
> > > aggregate(data[, some.columns], list(data$factor1, data$factor2), max)
> > >
> > > will give you maximum for specified columns based on spliting the data
> > > according to both factors
> > >
> > > Also connection summary with max is not common and I wonder what is
> > > your output in this case. I believe that there are six same numbers.
> > > However R is case sensitive and maybe Max does something different
> > > from max. In my case it throws an error.
> > >
> > > HTH
> > > Petr
> > >
> > > On 8 Sep 2006 at 8:06, Graham Smith wrote:
> > >
> > > Date sent:            Fri, 8 Sep 2006 08:06:16 +0100
> > > From:                 "Graham Smith" <myotisone at gmail.com>
> > > To:                   r-help at stat.math.ethz.ch
> > > Subject:              [R] subsetting a data set
> > >
> > > > I have a data set called GQ1, which has 20 variables one of which is
> > > > a factor called Status at thre levels "Expert", "Ecol" and "Stake"
> > > >
> > > > I have managed to evaluate some of the data split by status using
> > > > commands like:
> > > >
> > > > summary (Max[Status=="Ecol"])
> > > >
> > > > BUT how do I produce  asummary for Ecol and Expert combined, the
> > > > only example I can find suggsts I could use
> > > >
> > > > summary (Max[Status=="Ecol"& Status=="Expert"]) but that doesn't
> > > > work.
> > > >
> > > > Additionally on the same vein, if I cannot work out how to create a
> > > > new data set that would contain all the data for all the variables
> > > > but only for the data where Status = Ecol, or where status equalles
> > > > Ecol and Expert.
> > > >
> > > > I know this is yet again a very simple problem, but I really can't
> > > > find the solution in the help or the books I have.
> > > >
> > > > Many thanks,
> > > >
> > > > Graham
> > > >
> > > >  [[alternative HTML version deleted]]
> > > >
> > > > ______________________________________________
> > > > R-help at stat.math.ethz.ch 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.
> > >
> > > Petr Pikal
> > > petr.pikal at precheza.cz
> > >
> > > ______________________________________________
> > > R-help at stat.math.ethz.ch 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.
> >
> > Petr Pikal
> > petr.pikal at precheza.cz
> >
> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>