Function MakeArrayInterfaceFromRDataFrame

R-package/src/xgboost_R.cc:174–213

}

[[nodiscard]] std::string MakeArrayInterfaceFromRDataFrame(SEXP R_df) {
  auto make_vec = [&](auto const *ptr, std::size_t len) {
    auto v = xgboost::linalg::MakeVec(ptr, len);
    return xgboost::linalg::ArrayInterface(v);
  };

  R_xlen_t n_features = Rf_xlength(R_df);
  std::vector<xgboost::Json> array(n_features);
  CHECK_GT(n_features, 0);
  std::size_t len = Rf_xlength(VECTOR_ELT(R_df, 0));

  // The `data.frame` in R actually converts all data into numeric. The other type
  // handlers here are not used. At the moment they are kept as a reference for when we
  // can avoid making data copies during transformation.
  for (R_xlen_t i = 0; i < n_features; ++i) {
    switch (TYPEOF(VECTOR_ELT(R_df, i))) {
      case INTSXP: {
        auto const *ptr = INTEGER(VECTOR_ELT(R_df, i));
        array[i] = make_vec(ptr, len);
        break;
      }
      case REALSXP: {
        auto const *ptr = REAL(VECTOR_ELT(R_df, i));
        array[i] = make_vec(ptr, len);
        break;
      }
      case LGLSXP: {
        auto const *ptr = LOGICAL(VECTOR_ELT(R_df, i));
        array[i] = make_vec(ptr, len);
        break;
      }
      default: {
        LOG(FATAL) << "data.frame has unsupported type.";
      }
    }
  }

  xgboost::Json jinterface{std::move(array)};
  return xgboost::Json::Dump(jinterface);
}

void AddMissingToJson(xgboost::Json *jconfig, SEXP missing, SEXPTYPE arr_type) {
  if (Rf_isNull(missing) || ISNAN(Rf_asReal(missing))) {