[R] ROCR package question

[Tobias Sing]

Waverley, see help('performance-class') for a description of the slots.

Your AUCs will be in perf at y.values, which itself is a list (one list
element per run).

Thus, you can use functions like unlist or s/lapply to access them, e.g.
mean(unlist(perf at y.values))

Kind regards,
  Tobias

On Sat, Jul 25, 2009 at 5:44 PM, Waverley<waverley.paloalto at gmail.com> wrote:
> Thanks for the reply.  I am not sure I am following:
>
> 1. for the sample code.  I tried perf at auc but get auc object not found
> 2. I am SPECIFICALLY interested in the averaged auc value of the
> multiple runs.  How to get that out?  I typed perf and it comes out as
> a list.
> 3. as for the plot using whisker plot to see the distribution of the
> multiple runs, the outliers outside the whisker is very annoying.  How
> to get rid of the "outline" which is outside the whisker?  I tried to
> use boxplot option and put in the following plot code as an option
> outline=FALSE and it did not work.
>
> Please help me with the specifics of the above 3 questions.  Use code
> instead of description would be helpful.
>
> Thanks a lot in advance.
>
>
>
>>Waverley,
>
>>use @ (instead of $) to extract the slots from the performance object (it's S4 class system).
>
>>HTH,
>>  Tobias
>
> On Sat, Jul 25, 2009 at 8:20 AM, Waverley<waverley.paloalto at gmail.com> wrote:
>> I use ROCR to plot multiple runs' performance.  Using the sample code
>> as example:
>>
>> # plot ROC curves for several cross-validation runs (dotted # in
>> grey), overlaid by the vertical average curve and boxplots # showing
>> the vertical spread around the average.
>> data(ROCR.xval)
>> pred <- prediction(ROCR.xval$predictions, ROCR.xval$labels) perf <-
>> performance(pred,"tpr","fpr")
>> plot(perf,col="grey82",lty=3)
>> plot(perf,lwd=3,avg="vertical",spread.estimate="boxplot",add=TRUE)
>>
>> I can follow the code and plot without any problem.  However, I don't
>> know how to extract the averaged ROC area under curve value.
>>
>> Can someone help?
>>
>> Thanks.
>>
>> --
>> Waverley @ Palo Alto
>>
>> ______________________________________________
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>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
> --
> Waverley @ Palo Alto
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>