Re: [R] subsetting a data set

From: Graham Smith <myotisone_at_gmail.com>
Date: Fri 08 Sep 2006 - 09:03:51 GMT

Petr,

Thanks I shall have at look at these options.

Sorry about the confusion with the "Max", in my example "Max" is the name of the variable that I am summarising. I chose a poor example to cut and paste form R, not thinking about the obvious confusion this would cause.

Thanks again

Graham

On 08/09/06, Petr Pikal <petr.pikal@precheza.cz> wrote:
>
> 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@gmail.com>
> To: r-help@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@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@precheza.cz
>
>

        [[alternative HTML version deleted]]



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