[R] (no subject)

[Liaw, Andy]

What you've shown us looks inconsistent:  The data frame you show has
variables X1 through X5 and `class'.  If this is a data frame named `data',
why do you call tree() with the formula V1 ~ X1?  Where is V1?

`data' is the name of a built-in R function.  Try using some other name for
the data frame.  Also, give us the output of traceback() after the error
occur.  That should help.

Andy

> From: NICOLAS DEIG
> 
> hello,
> 
> I am encoutering problems with a function of R. 
> The function is for classification trees. 
> 
> I am working on datas of this kind:
> 
>        X1    X2    X3    X4    X5   class
> 1   2.092 1.902 2.779 2.944 1.946       1
> 
> for 200 observations and 4 differents classes.
> 
> What i would like to do is grow a tree with the function 
> "tree" and then
> use the result in the function "cv.tree" in order to ran cross
> validation experiment. 
> > library(tree)
> > Z<-tree(V1~X1,data)
> > W<-cv.tree(Z)
> Error in as.data.frame.default(data) : can't coerce function into a
> data.frame
> 
> 
> There is the problem, "cv.tree" won t consider the resluts of function
> "tree" as an object of class tree, it just considers this object as a
> data frame. 
> Can anyone eyplain me why or already encoutered this kind of problem?
> 
> THanks in advance,
> Nicolas
> 
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