constructing a Data Frame in Rcpp

Question

I want to construct a data frame in an Rcpp function, but when I get it, it doesn\'t really look like a data frame. I\'ve tried pushing vectors etc. but it leads to the same

Answer 1

Briefly:

• DataFrames are indeed just like lists with the added restriction of having to have a common length, so they are best constructed column by column.

• The best way is often to look for our unit tests. Her inst/unitTests/runit.DataFrame.R regroups tests for the DataFrame class.

• You also found the .push_back() member function in Rcpp which we added for convenience and analogy with the STL. We do warn that it is not recommended: due to differences with the way R objects are constructed, we essentially always need to do full copies .push_back is not very efficient.

• Despite me answering here frequently, the rcpp-devel list a better place for Rcpp questions.