CODEWITHSUNDEEP
r
Raj
Raj

Reputation: 53

How to correct the error in plotting the ROCR plot?

Error in performance(pred, "tpr", "fpr") : Wrong argument types: First argument must be of type 'prediction'; second and optional third argument must be available performance measures!

s <- svm(Column20 ~ ., data =train) 
pred <- predict(s, test[,-20]) 
x <-table( pred, test$Column20) 
P <- performance(x, "tpr", "fpr")

if I change this line of code as x <-prediction( pred, test$Column20), im getting this error 

 Error in prediction(pred, test$Column20) : 
  Format of predictions is invalid.

I do not understand the error properly.could you please explain what I have done wrong? Thanks in advance

Upvotes: 1

Views: 3189

Answers (1)

Marco Sandri
Marco Sandri

Reputation: 24272

Here is a simple illustrative example. I hope it can help you.

library(e1071)
library(ROCR)

df <- iris[,1:4]
df$virgi <- as.numeric(iris$Species=="virginica")
svmMod <- svm(virgi ~ ., data = df)

svmPred <- predict(svmMod, df[,-5]) 

svmPredictiction <- prediction(svmPred, df$virgi)
svmPerf <- performance(svmPredictiction, "tpr", "fpr")

plot(svmPerf)

enter image description here

Upvotes: 1

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