R help - Aug 2012 - Class that wraps Data Frame

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.

Thanks in advance,

Ramiro

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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