[R] data encapsulation with classes

Roger Bivand Roger.Bivand at nhh.no
Sun Apr 8 15:08:18 CEST 2007

On Sun, 8 Apr 2007, Peter Williams wrote:

> Hi All,
> I'm new to R from a C and Octave/Matlab background.  I am trying to  
> construct some classes in R to which I want to attach pieces of data.
> First, is attr(obj, 'member name') <- data the accepted way of doing  
> this?

No, it isn't. You seem to be trying to deduce new-style classes from a
representation used before R 2.4, but in any case it would not be
sensible. Please consult John M. Chambers. Programming with Data.
Springer, New York, 1998, and/or William N. Venables and Brian D. Ripley.
S Programming. Springer, New York, 2000, or for a shorter online resource:


> Second, having attached member data with attr is there anything wrong  
> with accessing it by the asperand (@), i.e.
>  > t = ""
>  > attr(t, 'test') <- 4
>  > t at test
> [1] 4
> I can't find any documentation on using the asperand to access  
> attributes like this.  I saw it in a piece of code as I was googling  
> around trying to find some information on attaching data to a class  
> in R.  Is this deprecated?  Is this poor form?  If anyone has some  
> suggestions please let me know.
> Thank you
> ______________________________________________
> 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
> and provide commented, minimal, self-contained, reproducible code.

Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no

More information about the R-help mailing list