[R] Abstract classes
chuck at sharpsteen.net
Thu Mar 25 17:02:10 CET 2010
Albert-Jan Roskam wrote:
> Hi R lovers,
> I'm looking for more information about, and implementations of abstract
> classes. After reading "Head First Design Patterns" (O'Reilly). I want to
> know whether I could use this to build an interface, i.e. a placeholder
> for all possible methods in the underlying subclasses. The final goal is
> to end up with a more flexible/extensible design than could be achieved
> with inheritance and polymorphism.
> I installed the 'sp' package, because I read that the Spatial Class is an
> abstract class, but I don't know where to look for the file where that
> class lives. I tried, among others, the files in:
It looks like you were looking in the R library where R stores sp after
installing it- the problem with this is that R converts all the code to a
binary format and stores it in a single file. You want to download the
source tarball from CRAN:
Untar it and look in the R directory of the resulting folder. You will see
a file called Class-Spatial.R that contains the S4 class definition.
Another good study in S4 inheritance is the Matrix package which is now
included in the R core. You can download it's source from:
Look at the file called AllClass.R
Hope this helps!
Undergraduate-- Environmental Resources Engineering
Humboldt State University
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