void dataframe_define_test()
{
	stringstream root_path;
	root_path<<"./test.root";

	ROOT::EnableImplicitMT(2);
	TChain chain("tree");

	chain.Add(root_path.str().c_str());
	ROOT::RDataFrame d(chain);

	auto N=d.Define("y",[](int x){
			if("d1<0"){
			return x;
			}
			if("d1>0"){
			return x;
			}
			},{"d1"}).Take<int>("y");

	vector<int> &N_=*N;

	for(int i=0;i<(end(N_)-begin(N_));i++){
	cout<<N_[i]<<endl;
	}
}