[Rcpp-devel] retrieve the column names of Rcpp::DataFrame

[Kevin Ushey]

df.attr("names") ? data.frames do not have a column names attribute.
Neither do matrices, for that matter, which have an (optional) `dimnames`
attribute.

Please see: http://gallery.rcpp.org/articles/setting-object-attributes/,
and also try looking at what e.g. `attributes(data.frame(x=1))`, for
example, gives you to have a hint at what attributes you can poke at and
how.

Cheers,
Kevin


On Thu, Jul 10, 2014 at 5:09 PM, Chaomei Lo <chaomeilo at gmail.com> wrote:

> I have a R data frame pass to the Rcpp function, for example in below-
>
> void myDataFrame(Rcpp::DataFrame df) {
> ....
> }
>
> I would need to know the column names first before I retrieve the data but
> df.colnames() does not work but the df.length() and df.nrows() work.
>
> Thanks for help !
> Chaomei
>
>
>
>
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