[R] Using package ROCR

wiener30 ekliokys at yahoo.com
Fri Feb 27 10:19:41 CET 2009


Just an update concerning an error message in using ROCR package.

Error in as.double(y) : 
  cannot coerce type 'S4' to vector of type 'double' 

I have changed the sequence of loading the packages and the problem has
gone:
library(ROCR)
library(randomForest)

The loading sequence that caused an error was:
library(randomForest)
library(ROCR)

May be this info could be useful for somebody else who is getting the same
error.




wiener30 wrote:
> 
> Thank you very much for the response!
> 
> The plot(1,1) helped to resolve the first problem.
> But I am still getting a second error message when running demo(ROCR)
> 
> Error in as.double(y) : 
>   cannot coerce type 'S4' to vector of type 'double'
> 
> It seems it has something to do with compatibility of S4 objects.
> 
> My versions of R and ROCR package are the same as you listed.
> But it seems something other is missing in my installation.
> 
> 
> William Doane wrote:
>> 
>> 
>> Responding to question 1... it seems the demo assumes you already have a
>> plot window open.
>> 
>>   library(ROCR)
>>   plot(1,1)
>>   demo(ROCR)
>> 
>> seems to work.
>> 
>> For question 2, my environment produces the expected results... plot
>> doesn't generate an error:
>>   * R 2.8.1 GUI 1.27 Tiger build 32-bit (5301)
>>   * OS X 10.5.6
>>   * ROCR 1.0-2
>> 
>> -Wil
>> 
>> 
>> 
>> wiener30 wrote:
>>> 
>>> I am trying to use package ROCR to analyze classification accuracy,
>>> unfortunately there are some problems right at the beginning.
>>> 
>>> Question 1) 
>>> When I try to run demo I am getting the following error message
>>>> library(ROCR)
>>>> demo(ROCR)
>>>> if(dev.cur() <= 1) .... [TRUNCATED] 
>>> Error in get(getOption("device")) : wrong first argument
>>> When I issue the command
>>>> dev.cur() 
>>> it returns
>>> null device 
>>>           1
>>> It seems something is wrong with my R-environment ?
>>> Could somebody provide a hint, what is wrong.
>>> 
>>> Question 2)
>>> When I run an example commands from the manual
>>> library(ROCR)
>>> data(ROCR.simple)
>>> pred <- prediction( ROCR.simple$predictions, ROCR.simple$labels )
>>> perf <- performance( pred, "tpr", "fpr" )
>>> plot( perf )
>>> 
>>> the plot command issues the following error message
>>> Error in as.double(y) : 
>>>   cannot coerce type 'S4' to vector of type 'double'
>>> 
>>> How this could be fixed ?
>>> 
>>> Thanks for the support
>>> 
>>> 
>> 
>> 
> 
> 

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