R help - Jul 2008 - Object-oriented programming in R for Java programmers?

Hi,

I was wondering if anybody might have a reference for
me: My R code is growing and getting more and more
confusing. Thus, I figure it's time to switch to
object-oriented again. I have done oo programming in
C++ and Java before but the first few tutorial on R oo
were a bit confusing for me. 

Is there any brief tutorial on oo programming in R
especially for people who have done oo in Java or C++
before? That would be really helpful.

Many thanks and have a great Sunday,
  Werner


      __________________________________________________________

Dem pfiffigeren Posteingang.

Werner Wernersen <pensterfuzzer at yahoo.de> [Sun, Jul 27, 2008 at
01:55:26PM CEST]:
[...]
> Is there any brief tutorial on oo programming in R
> especially for people who have done oo in Java or C++
> before? That would be really helpful.
"How S4 methods work" highlights the differences between R's
function-centric
approach to OO and the class-centric approach highlighted by languages such
as C++. This 10-page article is written by John Chambers.

-- 
Johannes H?sing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes at huesing.name  from such a trifling investment of fact.
http://derwisch.wikidot.com         (Mark Twain, "Life on the
Mississippi")

Werner Wernersen wrote:
> 
> I have done oo programming in C++ and Java before but the first few
> tutorial on R oo were a bit confusing for me. 
> 
My personal experience is that the type of OO programming that makes for
example Java code nice and easy to structure is not possible in R. The
biggest problem for me is, correct me if i'm wrong, that R does not store
memory references in its identifiers (variables), but a creates new
'object'
for every identifier. For example, if you do in R:
a <- 123
b <- 456
a <- b
a <- 789
b

If you would do a similar thing in Java, bot the variables 'a' and
'b' would
have changed to the value 789, because both the variables now refer to the
same object. So manipulating one also manipulates the other. However, in R,
variable 'b' still stores the value of 456 at the end of this example.

What this means for OO programming is that there is no easy way to reference
to objects. For example, if you have want to access a variable which is part
of a dataframe object, which is nested in a list object, you can only
reference this object every time using list$dataframe$varname, where in
Java, you could create a new variable that references to this specific
object. Once datastructures become more complex, this handicap gets bigger
and bigger.

However, please don't take this for granted since I am only a beginning R
programmer (and slightly more advanced Java programmer). I am also really
curious what others have to say because I am having the same problem of my
R-code quickly getting messy and confusing.
-- 
View this message in context:
http://www.nabble.com/Object-oriented-programming-in-R-for-Java-programmers--tp18675688p18679872.html
Sent from the R help mailing list archive at Nabble.com.

I've never used it myself but I recall reading about this R.oo package a
while ago - might be worth considering?

http://www1.maths.lth.se/help/R/R.oo/



----- Original Message ----
From: Werner Wernersen <pensterfuzzer at yahoo.de>
To: r-help at stat.math.ethz.ch
Sent: Sunday, July 27, 2008 4:55:26 AM
Subject: [R] Object-oriented programming in R for Java programmers?

Hi,

I was wondering if anybody might have a reference for
me: My R code is growing and getting more and more
confusing. Thus, I figure it's time to switch to
object-oriented again. I have done oo programming in
C++ and Java before but the first few tutorial on R oo
were a bit confusing for me. 

Is there any brief tutorial on oo programming in R
especially for people who have done oo in Java or C++
before? That would be really helpful.

Many thanks and have a great Sunday,
  Werner


      __________________________________________________________

Dem pfiffigeren Posteingang.

______________________________________________
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.

This page is also a brief introduction to the S3 classes:

http://www.ibm.com/developerworks/linux/library/l-r3.html

(see section on 'Object-oriented R')

and for S4, in addition to "How S4 methods work":

http://developer.r-project.org/methodDefinition.html



----- Original Message ----
From: Johannes Huesing <johannes at huesing.name>
To: r-help at r-project.org
Sent: Sunday, July 27, 2008 12:21:37 PM
Subject: Re: [R] Object-oriented programming in R for Java programmers?

Werner Wernersen <pensterfuzzer at yahoo.de> [Sun, Jul 27, 2008 at
01:55:26PM CEST]:
[...]
> Is there any brief tutorial on oo programming in R
> especially for people who have done oo in Java or C++
> before? That would be really helpful.
"How S4 methods work" highlights the differences between R's
function-centric
approach to OO and the class-centric approach highlighted by languages such
as C++. This 10-page article is written by John Chambers.

-- 
Johannes H?sing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes at huesing.name  from such a trifling investment of fact.
http://derwisch.wikidot.com         (Mark Twain, "Life on the
Mississippi")

______________________________________________
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.