performance() doesn't return any value

[CHENGHAO-WANG]

Thanks so much for the nice package.

I meant to make an ROC plot and calculate the AUC. But I couldn't get the AUC somehow.

> lda.posterior <- predict(fit.lda, dat.dr, type="raw")
> pred <- prediction(lda.posterior$posterior[,2],dat.dr$is_female)
> perf <- performance(pred,"tpr","fpr")
> plot(perf,xlab="1-specificity",ylab="sensitivity") # I had no issue with this step. I got a nice ROC plot.
> performance(pred,"auc")
A performance instance
  'Area under the ROC curve'

No error messages. But AUC wasn't shown up.

[Felix Ernst]

It is not printed, when printing the object, but it is calculated.

Why didn't you assign the output of performance(pred,"auc") to a new object?

How about this:

perf2 <- performance(pred,"auc")
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For more details see ?performance-class``