[Rcpp-devel] Performance question about DataFrame

[John Merrill]

You're confusing a data frame object with the data.frame coercion function.
 Data frames themselves are fast to access.  The coercion function is not.


On Tue, Jan 15, 2013 at 7:36 AM, Yan Zhou <zhouyan at me.com> wrote:

> I am curious what usage of data.frame give you the conclusion that it is
> slow. You must know that data.frame IS a list of variables, which can be
> vectors (though not always) and can only be faster than a list of lists.
>
> Best,
>
> Yan
>
>
> On Jan 15, 2013, at 03:20 PM, John Merrill <john.merrill at gmail.com> wrote:
>
> It appears that DataFrame::create is a thin layer on top of the R
> data.frame call.  The guarantee correctness, but also means the performance
> of an Rcpp routine which returns a large data frame is limited by the
> performance of data.frame -- which is utterly horrible.
>
> In the current version of R, there's a trivial, but borderline evil, work
> around: build a list of lists meeting the basic requirements of a data
> frame (they all need to be of the same length, and each component list
> needs to be named) and set the type of the object to "data.frame".
>
> I have two questions:
> (1) Is it reasonable to anticipate that this hack will continue to work
> for the near future in R?
> (2) If so, would a patch to that effect be of interest to the developers?
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