R help - Feb 2010 - Random Forest

Hi,
i'm using randomForest package and i have 2 questions:
1. Can i drop one tree from an RF object?
2. i have a 300 trees forest, but when i use the predict function on new
data (with predict.all=TRUE) i get only 270 votes. did i do something wrong?
Thanks

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From: Dror
> 
> Hi,
> i'm using randomForest package and i have 2 questions:
> 1. Can i drop one tree from an RF object?
Yes.
> 2. i have a 300 trees forest, but when i use the predict 
> function on new
> data (with predict.all=TRUE) i get only 270 votes. did i do 
> something wrong?
Try to follow the posting guide (link in the footer of the message) and
you may just get the help you're looking for.  Please help us to help
you!

Andy
> Thanks
> 
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Hi,
Thank you for your replies
as for the prediction length, i run this code:
"
library(arules)
data(AdultUCI)
AdultUCI$workclass<-factor(AdultUCI$workclass, levels
c(levels(AdultUCI$workclass), "UNKNOWN"))
AdultUCI$workclass[is.na(AdultUCI$workclass)]<-"UNKNOWN"
AdultUCI$occupation<-factor(AdultUCI$occupation, levels
c(levels(AdultUCI$occupation), "UNKNOWN"))
AdultUCI$occupation[is.na(AdultUCI$occupation)]<-"UNKNOWN"
AdultUCI$"native-country"<-factor(AdultUCI$"native-country",
levels c(levels(AdultUCI$"native-country"), "UNKNOWN"))
AdultUCI$"native-country"[is.na(AdultUCI$"native-country")]<-"UNKNOWN"
tt<-sort(table(AdultUCI$"native-country"))
AdultUCI$"native-country"<-factor(AdultUCI$"native-country",
levels c(levels(AdultUCI$"native-country"), "OTHER"))
AdultUCI$"native-country"[!is.na(match(AdultUCI$"native-country",names(tt[1:11])))]<-"OTHER"
drop=names(tt[1:11])
AdultUCI$"native-country"<-factor(AdultUCI$"native-country",
levels
levels(AdultUCI$"native-country")[-which(levels(AdultUCI$"native-country")
%in% drop)])
names(AdultUCI)=c("age","WorkClass","fnlwgt","Education","educationNum","maritalStatus","occupation","relationship","race","sex","capitalGain","capitalLoss","hoursPerWeek","nativeCountry","YearIncome")
adult<-AdultUCI[1:32561,]
library(randomForest)
frf=formula(YearIncome~age+WorkClass+fnlwgt+Education
		+educationNum+maritalStatus+occupation
		+relationship+race+sex+capitalGain+capitalLoss
		+hoursPerWeek+nativeCountry)

{RF=randomForest(data=adult
	,frf
	,ntree=200
	,mtry=4
	,keep.forest=TRUE)
}
pr<-predict(RF,adult[1,],predict.all=TRUE)
"
and get this results:
> str(pr)
List of 2
 $ aggregate : Factor w/ 2 levels "small","large": 1
 $ individual: chr [1, 1:198] "small" "small"
"small" "small" ...
  ..- attr(*, "dimnames")=List of 2
  .. ..$ : chr "1"
  .. ..$ : NULL
> 
why don't i have 200 votes?
Thanks,
Dror
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