R help - Sep 2011 - Fwd: FSelector and RWeka problem

Hi all,

Although I sent the mail to Piotr, the author of FSelector, it should be better
to ask here to let others know.


Yanwei





Begin forwarded message:

From: Yanwei Song <yanwei.song@gmail.com>
Date: September 7, 2011 4:41:58 PM EDT
To: p.romanski@stud.elka.pw.edu.pl
Subject: FSelector and RWeka problem

Dear Piotr,

Thanks for developing the FSelector package for us. I'm a new R beginner,
and trying to use R to do some machine learning related research.
Here is the problem I found:

I was trying to combine RWeka and FSelector, and do the forward feature
selection with J48/C5.4 decision tree:

Here is the code:
#=================library(RWeka)
library(FSelector)
library(rpart)

                                                                     
data(iris)
evaluator <- function(subset) {
 p <- J48(as.simple.formula(subset, "Species"), data=iris)
 e <- evaluate_Weka_classifier(p)
 print(subset)
 print(e$details[1])
 return(e$details[1])
}


subset <- forward.search(names(iris)[-5], evaluator)
========================I got this error, when I ran it:

Error in paste(attributes, sep = "", collapse = " + ") :
 cannot coerce type 'closure' to vector of type 'character'

Not sure if you can help me out, I was stuck by this for a whole day as a
beginner.

Thanks


Best Regards,

Yanwei



	[[alternative HTML version deleted]]

Hi all,

Last post didn't give the plain format:

I was trying to combine RWeka and FSelector, and do the forward feature
selection with J48/C5.4 decision tree:

Here is the code:
#=================library(RWeka)
library(FSelector)
library(rpart)

                                                                     
data(iris)
evaluator <- function(subset) {
 p <- J48(as.simple.formula(subset, "Species"), data=iris)
 e <- evaluate_Weka_classifier(p)
 print(subset)
 print(e$details[1])
 return(e$details[1])
}


subset <- forward.search(names(iris)[-5], evaluator)
========================I got this error, when I ran it:

Error in paste(attributes, sep = "", collapse = " + ") :
 cannot coerce type 'closure' to vector of type 'character'

I don't know how I could fix this problem.
Thanks.


Yanwei