R help - Aug 2005 - Puzzled at rpart prediction

I'm in a situation where I say:
> predict(m.rpart, newdata=D[N1+t,])
      0   1
173 0.8 0.2

which I interpret as meaning: an 80% chance of "0" and a 20% chance of
"1". Okay. This is consistent with:
> predict(m.rpart, newdata=D[N1+t,], type="class")
[1] 0
Levels: 0 1

But I'm puzzled at the following. If I say:
> predict(m.rpart, newdata=D[N1+t,], type="vector")
173 
  1 

What gives?

I will be happy to packup a runnable demonstration for any of you, but
I wondered if it was just my lack of knowledge about "type" in
predict.rpart; wondered if there was a simple and logical explanation.

-- 
Ajay Shah                                                   Consultant
ajayshah at mayin.org                      Department of Economic Affairs
http://www.mayin.org/ajayshah           Ministry of Finance, New Delhi

Ajay Narottam Shah wrote:
> I'm in a situation where I say:
> 
> 
>>predict(m.rpart, newdata=D[N1+t,])
> 
>       0   1
> 173 0.8 0.2
> 
> which I interpret as meaning: an 80% chance of "0" and a 20%
chance of
> "1". Okay. This is consistent with:
> 
> 
>>predict(m.rpart, newdata=D[N1+t,], type="class")
> 
> [1] 0
> Levels: 0 1
> 
> But I'm puzzled at the following. If I say:
> 
> 
>>predict(m.rpart, newdata=D[N1+t,], type="vector")
> 
> 173 
>   1 
> 
> What gives?
This means that the class of the first level is chosen, and the first 
level is "0".

Uwe Ligges

> I will be happy to packup a runnable demonstration for any of you, but
> I wondered if it was just my lack of knowledge about "type" in
> predict.rpart; wondered if there was a simple and logical explanation.
>