Hi Stacey, ROCR uses S4 classes. The elements are accessed using "@" instead of "$". You can find an example on slide 12 of the following slide deck: http://rocr.bioinf.mpi-sb.mpg.de/ROCR_Talk_Tobias_Sing.ppt
Also have a look at the R code that appears when you type "demo(ROCR)" in R which contains some more examples related to your question. Hope that helps, Tobias On Thu, May 22, 2008 at 8:32 PM, Jorge Ivan Velez <[EMAIL PROTECTED]> wrote: > Hi Stacey, > Try this: > > library(ROCR) > data(ROCR.simple) > pred <- prediction(ROCR.simple$predictions,ROCR.simple$labels) > perf <- performance(pred,"sens","spec") > cuts <- unlist(slot(perf,"alpha.values")) > cuts > > HTH, > > Jorge > > > On Thu, May 22, 2008 at 2:08 PM, Stacey Burrows <[EMAIL PROTECTED]> > wrote: > > > Hi, > > > > I have an object from the prediction function from the ROCR package and I > > would like to extract one of the slots from the object, for example the > > cutoffs slot. However the usual techniques ($, [["name"]]) of subsetting > > don't work. How can I assess the lists in the slots? > > > > Here is an example of what I am working with: > > > > library(ROCR) > > data(ROCR.simple) > > pred <- prediction(ROCR.simple$predictions,ROCR.simple$labels) > > > > > str(pred) > > Formal class 'prediction' [package "ROCR"] with 11 slots > > ..@ predictions:List of 1 > > .. ..$ : num [1:200] 0.613 0.364 0.432 0.140 0.385 ... > > ..@ labels :List of 1 > > .. ..$ : Ord.factor w/ 2 levels "0"<"1": 2 2 1 1 1 2 2 2 2 1 ... > > ..@ cutoffs :List of 1 > > .. ..$ : num [1:201] Inf 0.991 0.985 0.985 0.983 ... > > ..@ fp :List of 1 > > .. ..$ : num [1:201] 0 0 0 0 1 1 2 3 3 3 ... > > ..@ tp :List of 1 > > .. ..$ : num [1:201] 0 1 2 3 3 4 4 4 5 6 ... > > ..@ tn :List of 1 > > .. ..$ : num [1:201] 107 107 107 107 106 106 105 104 104 104 ... > > ..@ fn :List of 1 > > .. ..$ : num [1:201] 93 92 91 90 90 89 89 89 88 87 ... > > ..@ n.pos :List of 1 > > .. ..$ : int 93 > > ..@ n.neg :List of 1 > > .. ..$ : int 107 > > ..@ n.pos.pred :List of 1 > > .. ..$ : num [1:201] 0 1 2 3 4 5 6 7 8 9 ... > > ..@ n.neg.pred :List of 1 > > .. ..$ : num [1:201] 200 199 198 197 196 195 194 193 192 191 ... > > > > > > > Thanks in advance, > > Stacey > > > > > > --------------------------------- > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@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. > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@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. > [[alternative HTML version deleted]] ______________________________________________ R-help@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.
