Problems using Form when drawing a TTree branch

ROOT
1

Hi,

I want to loop over a load of branches of a TTree and draw each branch as a histogram. I’ve been trying to do this as follows:

TObjArray *branches = MyTree->GetListOfBranches();
int nbranches = branches->GetEntries();

for (int i = 0; i < nbranches; ++i) {
string branchname = ((TBranch*)(*branches)[i])->GetName();
MyTree->Draw(Form("%s>>hist", branchname),“m_PassCuts == 1”);
…
}

The problem I’ve been getting is errors like:

Error in TTreeFormula::Compile: Bad numerical expression : “�”

I’m using ROOT 5.29.02 using SL5. I used to use the same code in an older version of ROOT (v5.24.00) & in SL4 and it used to work fine so I’m not sure why it doesn’t work now.

Any ideas about how to solve this would be much appreciated!

Thanks,
Gemma

2

Hi,

You meantMyTree->Draw(Form("%s>>hist", branchname.c_str()),"m_PassCuts == 1");and I recommend to use MyTree->Draw(TString::Format("%s>>hist", branchname.c_str()),"m_PassCuts == 1");

Cheers,
Philippe.

3

Hi Philippe,

Thanks, that worked perfectly!

Cheers,
Gemma