[R] Class that wraps Data Frame

[David Winsemius]

On Aug 31, 2012, at 5:57 AM, Ramiro Barrantes wrote:

> Hello,
> 
> I have again a "good practices"/programming theory question regarding data.frames.
> 
> One of the fundamental objects that I use is the data frame with a particular set of columns that I would fill or get information from, and an entire system would revolve around getting information from or putting information to such data.frame.
> 
> On a different OOP programming language I would be tempted to create a class that would "wrap-around" that data.frame and create "getters" and "setters" methods that would return whatever information I need. I started doing that using S4.
> 
> Does anyone have examples of packages that use that approach or any suggestions?  It just seems to me that a class/object would be a better idea because it would create a single, hopefully well validated way to access information and edit the fundamental data.frame object, which would be helpful if there are several programmers on the team and/or if some of the data.frame manipulations are not straightforward and are best left encapsulated in a method of a class, and then have people use that method.  I would just like to know if there are reasons not do it that way and if there are any examples of packages that use that approach and that I can learn from.

You could argue that the entire BioConductor project represents such an effort. It makes extensive use of S4 methods. I'm not a user so cannot readily point to examples of S4 functions that have set. and get. methods for particular sorts of dataframes, but I suspect you can pose the same question on the BioC mailing list and get a more informed answer.

-- 
David Winsemius, MD
Alameda, CA, USA