R help - May 2009 - Get (feature, threshold) from Output of rpart() for Stump Tree

Hi, 
I have a question regarding how to get some partial information
from the output of rpart, which could be used as the first argument to
predict. For example, in my code, I try to learn a stump tree (decision
tree of depth 2):

   "fit        <- rpart(y~bx, weights = w/mean(w), control = cntrl)
    print(fit)

    btest[1,]  <- predict(fit, newdata = data.frame(bx)) "

I found that "fit" is of  mode "list" and length 12. If I
"print(fit)", I will get as output:


"n= 124 
node), split, n, deviance, yval
      * denotes terminal node
1) root 124 61.54839 0.7096774  
  2) bx.21< 13.5 41 40.39024 0.1219512 *
  3) bx.21>=13.5 83  0.00000 1.0000000 *"



I don't want the whole output of "print(fit)" but only the two
kinds of
info in it: "21" in "bx.21", which I believe to be the
feature ID of
the stump tree , and 13.5, which I believe to be the threshold on the
feature.  If I am able to get these two out, then I will be able to
further process them or write them into a file.



Any hint?



Thanks and regards!



-Tim







      
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--- begin included message --
Hi, 
I have a question regarding how to get some partial information
from the output of rpart, which could be used as the first argument to
predict. For example, in my code, I try to learn a stump tree (decision
tree of depth 2):

?? "fit??????? <- rpart(y~bx, weights = w/mean(w), control = cntrl)

--- end inclusion ---

 1. For stump trees, you can use the depth option in rpart.control to get a 
small tree.  You also might want to set maxsurrogate=0 for speed.
 
 2. Try help(rpart.object) for more information on what is contained in the 
returned rpart object.  In your case fit$splits[1,] would contain all that you 
need.
 
 	Terry T.