[R] Question re labels in r-part (continuation of a thread from a while back)

[Peter Flom]

Hello again

I have modeled a tree using rpart, with the DV being a log
transformation of the variable I am really interested in (I transformed
the DV due to extreme skewness).  By default, text.rpart labels the
nodes with the value of yval, which in this case is not what I want; I'd
like the labels to be on the original metric, but label in text.rpart 
requires a  "column name of x$frame", and the original DV is not on that
frame.

So, I tried the following:

{create the tree}
tr.totpart <- rpart(log(totpart +1)  ~ sexfact + age + windle +
eabused
    + as.factor(pabau) + positive + controlling + lenient +
druguse.ever
    + anycsw,
    xval = 10,  cp = 0.000000001, data = duhray)



{prune the tree}
tr.totpart.pruned <- prune (tr.totpart, cp = .02)


{ad the original metric to the frame}


meanpart <- exp(tr.totpart.pruned$frame$yval)-1
tr.totpart.pruned$frame <- cbind(tr.totpart.pruned$frame, meanpart)


and thought this was good because summary(tr.totpart.pruned$frame)
lists meanpart as one of the columns.

BUT when I tried


plot(tr.totpart.pruned, compress = T, uniform = T, nspace = .5, margin
= .1)
text(tr.totpart.pruned, splits = T, all = T, pretty = 0, digits = 4,
use.n = T,  fancy = T, label = meanpart)

I got an error

Error in text.rpart(tr.totpart.pruned, splits = T, all = T, pretty = 0,
 : 
        Label must be a column label of the frame component of the
tree





Any thoughts or insights or help appreciated, as always

Peter

PS Given the recent posts on the thread about how to ask questions, I
should perhaps add that I have looked thru ?rpart, and through Atkinson
& Therneau (1997): An Introduction to recursive partitioning using the
RPART routines



Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core
Center for Drug Use and HIV Research
National Development and Research Institutes
71 W. 23rd St
www.peterflom.com
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)