R help - Jan 2012 - ctree question

Hello.  I have used the "party" package to generate a regression tree
as
   follows:

   >origdata<-read.csv("origdata.csv")
   >ctrl<-ctree_control(mincriterion=0.99,maxdepth=10,minbucket=10)
   >test.ct<-ctree(Y~X1+X2+X3,data=origdata,control=ctrl)

   The above works fine.  Orig data was my training data.  I now have a test
   data file (testdata), and would like to run the testdata through the above
   tree to see predictions.  I tried using the following function

   >predict(test.ct,newdata=testdata)

   but I get the following error:

   Error in checkData(oldData, RET) :
     Levels in factors of new data do not match original data
    
   I've looked at the testdata file closely and it does not appear to
contain
   any levels of factors that were not in the original.  What might I be doing
   incorrectly, and how can i use the tree that was generated above to generate
   predictions for this new file testdata?
   
   THanks.
   sean

On Wed, 18 Jan 2012, seanstclair at verizon.net wrote:
>
>   Hello.  I have used the "party" package to generate a
regression tree as
>   follows:
>
>   >origdata<-read.csv("origdata.csv")
>   >ctrl<-ctree_control(mincriterion=0.99,maxdepth=10,minbucket=10)
>   >test.ct<-ctree(Y~X1+X2+X3,data=origdata,control=ctrl)
>
>   The above works fine.  Orig data was my training data.  I now have a test
>   data file (testdata), and would like to run the testdata through the
above
>   tree to see predictions.  I tried using the following function
>
>   >predict(test.ct,newdata=testdata)
>
>   but I get the following error:
>
>   Error in checkData(oldData, RET) :
>     Levels in factors of new data do not match original data
>
>   I've looked at the testdata file closely and it does not appear to
contain
>   any levels of factors that were not in the original.
Did you check carefully enough? compare

levels(origdata$X1)
levels(testdata$X1)

and so on for X2 and X3. Maybe the _observed_ levels in the testdata are 
ok but not all levels.
Z
>   What might I be doing
>   incorrectly, and how can i use the tree that was generated above to
>   generate predictions for this new file testdata?
>
>   THanks.
>   sean
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