On Tue, 22 Jul 2003, Luis Miguel Almeida da Silva wrote:

> I didn't noticed that fact. I've already found a way to do that
>  
> x <- 1:40
> colnames(df.treino) <- paste("Ncp",x,sep=".")
>  
> and this generates names that I can relate with the variables. Thanks anyway
>  
> The problem is that I use rpart in a loop and the class labels are in the last 
> column. For the above example I would "type"
>  
> rpart(Ncp.40~.,data=df.treino)
>  
> But in the next step of the loop I can have only 35 variables and the class labels 
> would be at the Ncp.36. So I have to refresh the formula in rpart... and that is my 
> problem
> 

R> df.treino <- data.frame(matrix(rnorm(25), ncol=5))
R> thisformula <- as.formula(paste(colnames(df.treino)[ncol(df.treino)],
"~ ."))
R> thisformula
X5 ~ .
R> rpart(thisformula, data = df.treino)
n= 5 

node), split, n, deviance, yval
      * denotes terminal node

1) root 5 3.032904 -0.3392065 *

Torsten


>       -----Original Message----- 
>       From: Torsten Hothorn [mailto:[EMAIL PROTECTED] 
>       Sent: Tue 22/07/2003 14:57 
>       To: Luis Miguel Almeida da Silva 
>       Cc: [EMAIL PROTECTED] 
>       Subject: Re: [R] variable names
>       
>       
> 
> 
>       On Tue, 22 Jul 2003, Luis Miguel Almeida da Silva wrote:
>       
>       > Dear helpers
>       > 
>       > I want to use rpart several times in a loop to build a classification tree. 
> My problem is that rpart needs a formula as argument and for that the variables need 
> to have names and this doesn't happen in my case. Every iteration in the loop has a 
> different dataset with several variables (ex. 38 or more) and so I can't type the 
> names by hand every time. Is there any function that generates names for variables 
> in a dataframe. If so, how can I use then the argument
>       > 
>       
>       If your data is organised in a data.frame, (dummy) variable names are
>       available by default:
>       
>       R> mydata <- data.frame(matrix(rnorm(25), ncol=5))
>       R> mydata
>                 X1          X2         X3         X4          X5
>       1  1.3806313 -0.41827136  0.9591628 -1.3351038  0.02746110
>       2  0.5114590 -1.34111439 -0.9617552 -0.8367088 -0.06913021
>       3 -1.7508089 -0.49387076 -1.7597395  2.3899490 -0.15209650
>       4 -1.6753809 -1.28381808 -1.0424903  0.1002998  0.27784949
>       5 -0.2605535 -0.09035652 -2.5786418  1.0483400 -0.70445615
>       R> rpart(X1 ~ ., data = mydata)
>       n= 5
>       
>       node), split, n, deviance, yval
>             * denotes terminal node
>       
>       1) root 5 7.463698 -0.3589306 *
>       
>       best,
>       
>       Torsten
>       
>       > rpart(classlabels~. ,.....)
>       > 
>       > thanks
>       >
>       > ______________________________________________
>       > [EMAIL PROTECTED] mailing list
>       > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>       >
>       >
>       
>       
> 
>

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