R help - Jan 2005 - (no subject)

hi,

I am trying to grow a classification tree on some data, but I have a little
problem. In order to do so I have to use a function like "tree" in R
and on the
internet help(tree) I get the following: 

"The left-hand-side (response) should be either a numerical vector when a
regression tree will be fitted or a factor, when a classification tree is
produced"

I would like to know what is a "factor" in R, is it numerical value
with no
formula or just a word??

Thanks in advance
Nicolas

On 12 Jan 2005 at 15:17, nicolas.deig at epfl.ch wrote:
> 
> hi,
> 
> I am trying to grow a classification tree on some data, but I have a
> little problem. In order to do so I have to use a function like
"tree"
> in R and on the internet help(tree) I get the following: 
> 
> "The left-hand-side (response) should be either a numerical vector
> when a regression tree will be fitted or a factor, when a
> classification tree is produced"
> 
> I would like to know what is a "factor" in R, is it numerical
value
> with no formula or just a word??
Hi Nicolas

?factor will show you what it is.


Description:

     The function 'factor' is used to encode a vector as a factor (the
     terms 'category' and 'enumerated type' are also used for 
factors).
      If 'ordered' is 'TRUE', the factor levels are assumed to
be
     ordered. For compatibility with S there is also a function
     'ordered'.

Cheers
Petr

> 
> Thanks in advance
> Nicolas
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
Petr Pikal
petr.pikal at precheza.cz

On Wed, 2005-01-12 at 15:17 +0100, nicolas.deig at epfl.ch
wrote:
> hi,
> 
> I am trying to grow a classification tree on some data, but I have a little
> problem. In order to do so I have to use a function like "tree"
in R and on the
> internet help(tree) I get the following: 
> 
> "The left-hand-side (response) should be either a numerical vector
when a
> regression tree will be fitted or a factor, when a classification tree is
produced"
> 
> I would like to know what is a "factor" in R, is it numerical
value with no
> formula or just a word??
> 
> Thanks in advance
> Nicolas
See ?factor and/or Chapter 4 "Ordered and Unordered Factors" in
"An
Introduction to R".

Also, you might want to look into the 'rpart' package for an alternative
to 'tree'. rpart is included in the base R distribution:

library(rpart)
?rpart

HTH,

Marc Schwartz

I think you will find all the doc in the help files
> ?factor()
  gets

   The function 'factor' is used to encode a vector as a factor (the
     terms 'category' and 'enumerated type' are also used for
factors).
      If 'ordered' is 'TRUE', the factor levels are assumed to
be
     ordered. For compatibility with S there is also a function
     'ordered'.

     'is.factor', 'is.ordered', 'as.factor' and
'as.ordered' are the
     membership and coercion functions for these classes.

Usage:

     factor(x, levels = sort(unique.default(x), na.last = TRUE),
            labels = levels, exclude = NA, ordered = is.ordered(x))
     ordered(x, ...)
etc...

c'est une  variable de type cat?gorique! whose levels (values) are strings

To get help:
type ?functionname
or if you are under Windows see the menu "Help\Html help" and look
under
Packages. What you will want first are the "Base" and
"Statistics" packages

Anne



----- Original Message ----- 
From: <nicolas.deig at epfl.ch>
To: <r-help at stat.math.ethz.ch>
Sent: Wednesday, January 12, 2005 3:17 PM
Subject: [R] (no subject)

>
> hi,
>
> I am trying to grow a classification tree on some data, but I have a
little
> problem. In order to do so I have to use a function like "tree"
in R and
on the
> internet help(tree) I get the following:
>
> "The left-hand-side (response) should be either a numerical vector
when a
> regression tree will be fitted or a factor, when a classification tree is
produced"
>
> I would like to know what is a "factor" in R, is it numerical
value with
no
> formula or just a word??
>
> Thanks in advance
> Nicolas
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

Hi all,

I've got a small, practical question, which untill now I couldn't solve 
(otherwhise I wouldn't mail it, right?) First of all, I'm talking about 
R 2.0.1 on a winxp system (using the default graphical interface being 
'Rgui').
When I make plots, using dates on the x-axis, it puts the labels in 
Dutch, which is nice (since it's my mother tongue) unless I want them in 
English... Is there a way to change this behaviour?  (Can I change the 
labels etc to English?)

tnx,
Kurt Sys