Method Project

cpp/src/arrow/acero/hash_join_node_test.cc:2165–2182

      }

      ExecBatch Project(JoinType join_type, const ExecBatch& batch) const {
        std::vector<Datum> values;
        if (join_type != JoinType::RIGHT_SEMI && join_type != JoinType::RIGHT_ANTI) {
          for (int i : left_output) {
            values.push_back(batch[i]);
          }
        }
        if (join_type != JoinType::LEFT_SEMI && join_type != JoinType::LEFT_ANTI) {
          int left_size =
              join_type == JoinType::RIGHT_SEMI || join_type == JoinType::RIGHT_ANTI
                  ? 0
                  : left->num_fields();
          for (int i : right_output) {
            values.push_back(batch[left_size + i]);
          }
        }
        return {std::move(values), batch.length};
      }
    };

    Projector GetProjector(std::vector<int> left_output, std::vector<int> right_output) {