From: Petr Pikal <petr.pikal_at_precheza.cz>

Date: Fri 08 Sep 2006 - 11:19:52 GMT

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. Received on Fri Sep 08 21:27:56 2006

Date: Fri 08 Sep 2006 - 11:19:52 GMT

Hi

On 8 Sep 2006 at 10:33, Graham Smith wrote:

Date sent: Fri, 8 Sep 2006 10:33:49 +0100 From: "Graham Smith" <myotisone@gmail.com> To: "Petr Pikal" <petr.pikal@precheza.cz> Copies to: r-help@stat.math.ethz.ch Subject: Re: [R] subsetting a data set

> 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,
*

look at ?factors how to deal with factors, if your variable is not a factor (see ?str) than turn it to one.

x<-sample(letters[1:3], 20, replace=T) #character
x.f<-as.factor(x) #turn to factor

*> x.f
*

[1] b c b a c a c a a a a a b c c c b b c b
Levels: a b c

*> levels(x.f)<-c("x","x","y") #rename levels
**> x.f
*

[1] x y x x y x y x x x x x x y y y x x y x
Levels: x y

*>
**>
*

> I want to analsye that at two levels: Expert and Ecol combined into a

*> new level called "AllEcol" and the exsiting level "Stake"
*

so in your case something like

GQ1$statusComb<-factor(GQ1$status, labels=c("AllEcol","AllEcol", "Stake"))

shall do it. Beware of label ordering!!!

BTW. It had been good if you provided a usable example, as stated in posting guide. Many times trying to elaborate an example I will solve the problem myself.

**HTH
**

Petr

*>
*

> It is this combining the levels that has got me stuck.

*>
**> Thanks again,
**>
**> Graham
**>
**> On 08/09/06, Petr Pikal <petr.pikal@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$status), summary)
**> >
**> > is maybe what you want.
**> > HTH
**> > Petr
**> >
**> >
**> > On 8 Sep 2006 at 10:31, Petr Pikal wrote:
**> >
**> > From: "Petr Pikal" <petr.pikal@precheza.cz>
**> > To: "Graham Smith" <myotisone@gmail.com>,
**> > r-help@stat.math.ethz.ch
**> > Date sent: Fri, 08 Sep 2006 10:31:12 +0200
**> > Priority: normal
**> > Subject: Re: [R] subsetting a data set
**> >
**> > > Hi
**> > >
**> > > I am not sure if your Max is the same as max so I am not sure what
**> > > you exactly want from your data. However you shall consult
**> > > ?tapply, ?by, ?aggregate and maybe also ?"[" together with chapter
**> > > 2 in intro manual in docs directory.
**> > >
**> > > aggregate(data[, some.columns], list(data$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@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
**> > >
**> > > ______________________________________________
**> > > 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]]
**>
**> ______________________________________________
**> 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

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. Received on Fri Sep 08 21:27:56 2006

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