R help - Jan 2011 - Extracting the terms from an rpart object

Hello all,

I wish to extract the terms from an rpart object.
Specifically, I would like to be able to know what is the response variable
(so I could do some manipulation on it).
But in general, such a method for rpart will also need to handle a "."
case
(see fit2)

Here are two simple examples:

fit1 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)
fit1$call
fit2 <- rpart(Kyphosis ~ ., data=kyphosis)
fit2$call


Is there anything "prettier" then using string manipulation?


Thanks.





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Details:-------------------------------------------------------
Contact me: Tal.Galili@gmail.com |  972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)
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Try this:

all.vars(terms(fit1))
all.vars(terms(fit2))


On Wed, Jan 26, 2011 at 3:33 PM, Tal Galili <tal.galili@gmail.com> wrote:
> Hello all,
>
> I wish to extract the terms from an rpart object.
> Specifically, I would like to be able to know what is the response variable
> (so I could do some manipulation on it).
> But in general, such a method for rpart will also need to handle a
"." case
> (see fit2)
>
> Here are two simple examples:
>
> fit1 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)
> fit1$call
> fit2 <- rpart(Kyphosis ~ ., data=kyphosis)
> fit2$call
>
>
> Is there anything "prettier" then using string manipulation?
>
>
> Thanks.
>
>
>
>
>
> ----------------Contact
> Details:-------------------------------------------------------
> Contact me: Tal.Galili@gmail.com |  972-52-7275845
> Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
> www.r-statistics.com (English)
>
>
----------------------------------------------------------------------------------------------
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

Take a look at the output of
   terms(fit2)
In particular
   tm <- terms(fit2)
   attr(tm, "response")
is 1 if there is a response and
   variables <- as.list(attr(tm, "variables"))[-1]
   variables[[1]]
gives the response expression if there is one.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com  
> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Tal Galili
> Sent: Wednesday, January 26, 2011 9:33 AM
> To: r-help at r-project.org
> Subject: [R] Extracting the terms from an rpart object
> 
> Hello all,
> 
> I wish to extract the terms from an rpart object.
> Specifically, I would like to be able to know what is the 
> response variable
> (so I could do some manipulation on it).
> But in general, such a method for rpart will also need to 
> handle a "." case
> (see fit2)
> 
> Here are two simple examples:
> 
> fit1 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)
> fit1$call
> fit2 <- rpart(Kyphosis ~ ., data=kyphosis)
> fit2$call
> 
> 
> Is there anything "prettier" then using string manipulation?
> 
> 
> Thanks.
> 
> 
> 
> 
> 
> ----------------Contact
> Details:-------------------------------------------------------
> Contact me: Tal.Galili at gmail.com |  972-52-7275845
> Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il 
> (Hebrew) |
> www.r-statistics.com (English)
> --------------------------------------------------------------
> --------------------------------
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>