The internal implementation of R's dataset

I am trying to build a data processing program. Currently I use a double matrix to represent the data table, each row is an instance, each column represents a feature. I also have an extra vector as the target value for each instance, it is of double type for regression, it is of integer for classifica开发者_JAVA技巧tion.

I want to make it more general. I am wondering what kind of structure R uses to store a dataset, i.e. the internal implementation in R.

Maybe if you inspect the rpy2 package, you can learn something about how data structures are represented (and can be accessed).

The internal data structures are `data.frame', a detailed introduction to the data frame can be found here.

http://cran.r-project.org/doc/manuals/R-intro.html#Data-frames