R help - Mar 2013 - why predict() gives zero length prediction?

I am new to R and start to play around naive bayes algorithm. But I run into a
problem which I could not figure out why: for the following sample data, the
predict function (using a naive bayes model) always gives me zero length.  Do
you have any hints? Thanks


Here is the code:
> titanic_small
  survived pclass
1        0      3
2        1      1
3        1      3
4        1      1
5        0      3
6        0      3
> model <- naiveBayes(survived~., data=titanic_small)
> prediction <- predict(model, titanic_small[,-1])
> length(prediction)
[1] 0

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If you look at the help for predict.naiveBayes, you can see that newdata is
supposed to be a data.frame.  However, you are providing newdata as a
vector, titanic_small[,-1].  Try using titanic_small[,-1, drop=FALSE]
instead.

Jean

On Tue, Mar 12, 2013 at 11:35 PM, S. Zhou <myxjtu@yahoo.com> wrote:
> titanic_small[,-1]
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