How to read tree?

[Timur]

Hello people! How to read the branch momentum.fCoordinates.fX in tree? SetBranchAddress gives nulls.
Peace of code:
Double_t m_x[4] = { 0 };
tree->SetBranchAddress(“momentum.fCoordinates.fX”, &m_x[]);

for (int ev = 0; ev <5; ev++) {

	tree->GetEntry(ev);
	
	for (int j = 0; j < 4; j++) {
		
		cout << m_x[j] << "	";
		v2[j].SetXYZT(m_x[j], m_y[j], m_z[j], m_t[j]);
		
	}
           cout << endl;

}

[amadio]

You need to have equivalent types for it to work. You will probably either have to use tree->SetBranchAddress(“momentum.fCoordinates”, &m_x); or set it for each component individually. In any case, have you looked at RDataFrame? It’s probably easier to use it to process your data.

[Timur]

Does it mean that in ROOT 5.34 version not include RDataFrame ?

[amadio]

That’s right, only ROOT 6.14 and above have RDataFrame. In ROOT 6.10 and 6.12 it was called TDataFrame and was part of the ROOT::Experimental namespace.