Thanks. It does work now.
I also get another problem when I use naivebayes and prediction in myapplication
There was anerror message:
Error in table(predict(nb.obj, test.data[, subset, drop = FALSE]), test.data[, :
all arguments must have the same length
The length of test.data[,subset, drop=FALSE] and test.data[,ncol(expr.matrix)] of are the same. I further checked length ofpredict(nb.obj, test.data[, subset, drop = FALSE]) is 0. I do not know why.
The script is shown below. I also attached test data
evaluator<- function(subset){
# k-fold cross validation
k<- 5
splits<- runif(nrow(expr.matrix))
results<- sapply(1:k, function(i){
test.indx<- (splits>= (i-1)/k)& (splits<i/k)
train.indx<- !test.indx
test.data<- expr.matrix[test.indx, , drop=FALSE]
train.data<- expr.matrix[train.indx, , drop=FALSE]
nb.obj<- naiveBayes(train.data[,subset, drop=FALSE], train.data[,ncol(expr.matrix)])
error.rate<- sum(predict(nb.obj,test.data[,subset, drop=FALSE]) == test.data[,ncol(expr.matrix)])/nrow(test.data)
return (error.rate)
})
print(subset)
print(mean(results))
return(mean(results))
}
subset<- best.first.search(colnames(expr.matrix)[-ncol(expr.matrix)], evaluator)
Br,
Luffy
On 05/05/2012 12:53 PM, Petr Savicky wrote:
> On Sat, May 05, 2012 at 09:21:10AM +0300, kiinalist wrote:
>> Hi,
>>
>> I tried to use naivebayes in package 'e1071'.
>> when I use following parameter, only one predictor, there is an error.
>>
>> > m<- naiveBayes(iris[,1], iris[,5])
>> > table(predict(m, iris[,1]), iris[,5])
>> Error in log(sapply(attribs, function(v) { :
>> Non-numeric argument to mathematical function
>>
>>
>> However, when I use two predictors, there is not error any more.
>>
>> > m<- naiveBayes(iris[,1:2], iris[,5])
>> > table(predict(m, iris[,1:2]), iris[,5])
>>
>> setosa versicolor virginica
>> setosa 49 0 0
>> versicolor 1 37 19
>> virginica 0 13 31
> Hi.
>
> A untested suggestion is to try
>
> m<- naiveBayes(iris[,1, drop=FALSE], iris[,5])
>
> The difference is that iris[,1] is not a dataframe, while
> both iris[,1:2] and iris[,1, drop=FALSE] are.
>
> Hope this helps.
>
> Petr Savicky.
>
> ______________________________________________
>
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>
https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide
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https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide
http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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