R help - May 2012 - what is Non-numeric argument to mathematical function in prediction ?

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

Do you know what is the problem?

Br,
Luffy

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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.