randomForests predict problem
Yves, Which version of the package are you using? I get:
soy <- na.omit(Soybean) ts <- sample(nrow(soy), 150, replace=FALSE) sb.rf <- randomForest(Class ~ ., data=soy[-ts,]) table(predict(sb.rf, soy[ts,], type="class"))
2-4-d-injury alternarialeaf-spot
0 37
anthracnose bacterial-blight
10 3
bacterial-pustule brown-spot
2 29
brown-stem-rot charcoal-rot
11 7
cyst-nematode diaporthe-pod-&-stem-blight
0 0
diaporthe-stem-canker downy-mildew
4 8
frog-eye-leaf-spot herbicide-injury
17 0
phyllosticta-leaf-spot phytophthora-rot
3 5
powdery-mildew purple-seed-stain
4 5
rhizoctonia-root-rot
5
Cheers,
Andy
-----Original Message----- From: Yves Brostaux [mailto:brostaux.y at fsagx.ac.be] Sent: Wednesday, April 02, 2003 4:46 AM To: r-help at stat.math.ethz.ch Subject: [R] randomForests predict problem Hello everybody, I'm testing the randomForest package in order to do some simulations and I get some trouble with the prediction of new values. The random forest computation is fine but each time I try to predict values with the newly created object, I get an error message. I thought I was because NA values in the dataframe, but I cleaned them and still got the same error. What am I doing wrong ?
> library(mlbench) > library(randomForest) > data(Soybean) > test <- sample(1:683, 150, replace=F) > sb.rf <- randomForest(Class~., data=Soybean[-test,]) > sb.rf.pred <- predict(sb.rf, Soybean[test,])
Error in matrix(t1$countts, nr = nclass, nc = ntest) :
No data to replace in matrix(...)
I did it the same way with rpart and all worked fine :
> library(rpart) > sb.rp <- rpart(Class~., data=Soybean[-test,]) > sb.rp.pred <- predict(sb.rp, Soybean[test,], type="class")
Thank you all for any advice you can give to me. -- Ir. Yves Brostaux - Statistics and Computer Science Dpt. Gembloux Agricultural University 8, avenue de la Facult? B-5030 Gembloux (Belgium) T?l : +32 (0)81 62 24 69 E-mail : brostaux.y at fsagx.ac.be Web : http://www.fsagx.ac.be/si/
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