R help - Mar 2008 - listing components of an object

Is there a method to list the components of an object, instead of looking at the
help for that method?  Let me be more clear with an example

data(iris)
  ## tune `svm' for classification with RBF-kernel (default in svm),
  ## using one split for training/validation set

  obj <- tune(svm, Species~., data = iris,
              ranges = list(gamma = 2^(-1:1), cost = 2^(2:4)),
              tunecontrol = tune.control(sampling = "fix")
             )

  ## alternatively:
  ## obj <- tune.svm(Species~., data = iris, gamma = 2^(-1:1), cost =
2^(2:4))

  summary(obj)
  plot(obj)
---------------------------------
For tune, an object of class tune, including the components:

best.parameters a 1 x k data frame, k number of parameters.
best.performance best achieved performance.
performances if requested, a data frame of all parameter combinations along with
the corresponding performance results.
train.ind list of index vectors used for splits into training and validation
sets.
best.model if requested, the model trained on the complete training data using
the best parameter combination.

I got the above by doing ?tune.

Is there a function that helps be do this?
Thanks ../Murli

On Mar 2, 2008, at 4:12 PM, Nair, Murlidharan T wrote:
> Is there a method to list the components of an object, instead of  
> looking at the help for that method?  Let me be more clear with an  
> example
>
> data(iris)
>   ## tune `svm' for classification with RBF-kernel (default in svm),
>   ## using one split for training/validation set
>
>   obj <- tune(svm, Species~., data = iris,
>               ranges = list(gamma = 2^(-1:1), cost = 2^(2:4)),
>               tunecontrol = tune.control(sampling = "fix")
>              )
>
>   ## alternatively:
>   ## obj <- tune.svm(Species~., data = iris, gamma = 2^(-1:1), cost  
> = 2^(2:4))
>
>   summary(obj)
>   plot(obj)
> ---------------------------------
> For tune, an object of class tune, including the components:
>
> best.parameters a 1 x k data frame, k number of parameters.
> best.performance best achieved performance.
> performances if requested, a data frame of all parameter  
> combinations along with the corresponding performance results.
> train.ind list of index vectors used for splits into training and  
> validation sets.
> best.model if requested, the model trained on the complete training  
> data using the best parameter combination.
>
> I got the above by doing ?tune.
>
> Is there a function that helps be do this?
Usually str(obj), or possibly as.list(obj) for many objects, will  
give you the sort of information that I think you want, but what's  
wrong with ?tune ? In other words, why do you want this list?  
Typically, it is advisable that one uses methods to access the  
components of an object, like for instance "coef(obj)" for the  
coefficients in a model object. This is so that the internal  
representation of an object can change without breaking your code,  
and a host of other reasons.
> Thanks ../Murli
Haris Skiadas
Department of Mathematics and Computer Science
Hanover College

Does

names(obj)

do what you want?


Patrick Burns
patrick at burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of S Poetry and "A Guide for the Unwilling S User")

Nair, Murlidharan T wrote:
>Is there a method to list the components of an object, instead of looking at
the help for that method?  Let me be more clear with an example
>
>data(iris)
>  ## tune `svm' for classification with RBF-kernel (default in svm),
>  ## using one split for training/validation set
>
>  obj <- tune(svm, Species~., data = iris,
>              ranges = list(gamma = 2^(-1:1), cost = 2^(2:4)),
>              tunecontrol = tune.control(sampling = "fix")
>             )
>
>  ## alternatively:
>  ## obj <- tune.svm(Species~., data = iris, gamma = 2^(-1:1), cost =
2^(2:4))
>
>  summary(obj)
>  plot(obj)
>---------------------------------
>For tune, an object of class tune, including the components:
>
>best.parameters a 1 x k data frame, k number of parameters.
>best.performance best achieved performance.
>performances if requested, a data frame of all parameter combinations along
with the corresponding performance results.
>train.ind list of index vectors used for splits into training and validation
sets.
>best.model if requested, the model trained on the complete training data
using the best parameter combination.
>
>I got the above by doing ?tune.
>
>Is there a function that helps be do this?
>Thanks ../Murli
>
>______________________________________________
>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.
>
>
>  
>