R help - Mar 2004 - How to collect trees grown by rpart

Jonathan,

Try making a list instead of an array.  See ?list.  Also, did you look into
random forests?  I'm not sure what you want to do, but there might be
methods there to do some of the work for you.

Sean

On 3/19/04 1:12 PM, "Jonathan Williams"
<jonathan.williams at pharmacology.oxford.ac.uk> wrote:
> I would like to collect the trees grown by rpart fits in an array,
> in order to be able to use them later to predict new data. I have
> tried to use parse and eval to do this, without success. I'd be
> very grateful if someone could explain how to do it.
> 
> The kind of thing I hope to do is:
> 
> resmat=array(NA, 100)
> for (run in 1:100) resmat[run]=rpart(y~., data=train[run])
> 
> So that, later, I can do:
> for (run in 1:100) pred[run]=predict(resmat[run], newdat)
> 
> But, resmat[run] does not work, even though it saves the cptables.
> 
> Thanks, in advance,
> 
> Jonathan Williams
> OPTIMA
> Radcliffe Infirmary
> Woodstock Road
> OXFORD OX2 6HE
> Tel +1865 (2)24356
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

I would like to collect the trees grown by rpart fits in an array,
in order to be able to use them later to predict new data. I have 
tried to use parse and eval to do this, without success. I'd be 
very grateful if someone could explain how to do it.

The kind of thing I hope to do is:

resmat=array(NA, 100)
for (run in 1:100) resmat[run]=rpart(y~., data=train[run])

So that, later, I can do:
for (run in 1:100) pred[run]=predict(resmat[run], newdat)

But, resmat[run] does not work, even though it saves the cptables. 

Thanks, in advance,

Jonathan Williams
OPTIMA
Radcliffe Infirmary
Woodstock Road
OXFORD OX2 6HE
Tel +1865 (2)24356

Yes, Jonathan has looked at randomForest, but for rpart trees, ipred might
be more appropriate.

Cheers,
Andy
> From:  Sean Davis
> 
> Jonathan,
> 
> Try making a list instead of an array.  See ?list.  Also, did 
> you look into
> random forests?  I'm not sure what you want to do, but there might be
> methods there to do some of the work for you.
> 
> Sean
> 
> On 3/19/04 1:12 PM, "Jonathan Williams"
> <jonathan.williams at pharmacology.oxford.ac.uk> wrote:
> 
> > I would like to collect the trees grown by rpart fits in an array,
> > in order to be able to use them later to predict new data. I have
> > tried to use parse and eval to do this, without success. I'd be
> > very grateful if someone could explain how to do it.
> > 
> > The kind of thing I hope to do is:
> > 
> > resmat=array(NA, 100)
> > for (run in 1:100) resmat[run]=rpart(y~., data=train[run])
> > 
> > So that, later, I can do:
> > for (run in 1:100) pred[run]=predict(resmat[run], newdat)
> > 
> > But, resmat[run] does not work, even though it saves the cptables.
> > 
> > Thanks, in advance,
> > 
> > Jonathan Williams
> > OPTIMA
> > Radcliffe Infirmary
> > Woodstock Road
> > OXFORD OX2 6HE
> > Tel +1865 (2)24356
> > 
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> >
> 
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
> 

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