Message-ID: <70667425-3B37-4357-B1DA-E49E7CD19605@comcast.net>
Date: 2009-11-24T14:10:43Z
From: David Winsemius
Subject: Decision trees with factors and numericals
In-Reply-To: <SNT104-W37BD8335B83D74ADF29BABB59D0@phx.gbl>
On Nov 24, 2009, at 8:50 AM, Joel F?rstenberg-H?gg wrote:
>
> Does any of you know how to make a decision tree when the data set
> contains factors and numericals?
>
> I've got a data frame with 3 columns, where y and x1 are numerical
> and x2 contains factors. Is it possible to use the rpart package,
> and in that case how? Otherwise, is there another alternative?
>
> This is what I've tried so far
>
>> rpart(LT50_NA ~ Raf + Antho, data=decTreeNA, method=anova) # Have
>> tried "method=class" as well
> Error in as.character(x) :
> cannot coerce type 'closure' to vector of type 'character'
>
I do not think that error is arising because you have a factor on the
RHS of the equation. It would have been extremely surprising to find
that rpart would be complaining about encountering a factor. I think
it is because you failed to enclose anova with quotes. The message is
telling you that R encountered a function (a closure) where it was
"hoping for" a character variable.
>
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT