[R] rpart$where and predict.rpart

[Chua Siang Li]

   Brian, thanks for the prompt reply.
   I am quite new to R and have no clue on how to call internal function.
   Tried the following but failed:
   > .Internal("pred.rpart")
   Error in .Internal("pred.rpart") : invalid .Internal() argument
   > .Internal()
   Error in .Internal() : 0 arguments passed to '.Internal' which requires 1
   > .Primitive("pred.rpart")
   Error in .Primitive("pred.rpart") : no such primitive function
   > .Primitive("rpart-internal")
   Error in .Primitive("rpart-internal") : no such primitive function
   So, I copy the whole source code into my codes
   pred.rpart <- function(fit, x) {

       frame <- fit$frame
       nc <- frame[, c('ncompete', 'nsurrogate')]
   :
   :
   }
   but still have error msg:
   >   where <- pred.rpart(mod, newdata=as.matrix(xLost))
   Error in pred.rpart(mod, newdata = as.matrix(xLost)) :
     unused argument(s) (newdata = c("1335.0", "1335.0", "1335.0", "1335.0",
   .....
   Btw, my predict function is ok.
   >  predictLost <- predict(mod, newdata=data.frame(y=yLost, x=xLost))
   Thanks.
   ----
   Chua Siang Li
   Consultant - Operations Research
   Acceval Pte Ltd
   Tel: 6297 8740
   Email: siang.li.chua at acceval-intl.com
   Website: www.acceval-intl.com
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   --------- Original Message --------
   From: "Prof Brian Ripley" <ripley at stats.ox.ac.uk>
   To: "Chua Siang Li" <siang.li.chua at acceval-intl.com>
   Cc: r-help at r-project.org
   Subject: Re: [R] rpart$where and predict.rpart
   Date: 07/22/08 18:51
   On Tue, 22 Jul 2008, Chua Siang Li wrote:
   >
   > Hello there. I have fitted a rpart model.
   > > rpartModel <- rpart(y~., data=data.frame(y=y,x=x),method="class", ....)
   > and can use rpart$where to find out the terminal nodes that each
   > observations belongs.
   > Now, I have a set of new data and used predict.rpart which seems to give
   > only the predicted value with no information similar to rpart$where.
   > May I know how to find out the terminal nodes that each new observations
   > belongs to?
   You need to read the code to answer questions about internals. A very
   quick glance at predict.rpart would have told you that
   where <- pred.rpart(object, rpart.matrix(newdata))
   is what you are looking for. (Note that pred.rpart like many other
   internal functions is not exported from the name space.)
   > Many thanks.
   > ----
   > Chua Siang Li
   > Consultant - Operations Research
   > Acceval Pte Ltd
   > Tel: 6297 8740
   > Email: [1]siang.li.chua at acceval-intl.com
   > Website: [2]www.acceval-intl.com
   --
   Brian D. Ripley, [3]ripley at stats.ox.ac.uk
   Professor of Applied Statistics, [4]http://www.stats.ox.ac.uk/~ripley/
   University of Oxford, Tel: +44 1865 272861 (self)
   1 South Parks Road, +44 1865 272866 (PA)
   Oxford OX1 3TG, UK Fax: +44 1865 272595

References

   1. mailto:siang.li.chua at acceval-intl.com
   2. http://www.acceval-intl.com/
   3. mailto:ripley at stats.ox.ac.uk
   4. http://www.stats.ox.ac.uk/~ripley/