Dear root users, The simplest way to histogram data from a tree is TTree::Draw. But I'd like to create histograms and then fill them with the leaves of a tree. I tried with the following macro: { // create an empty root file first TFile f("filename.root","new"); // create a histogram and fill it from a tree TH1F *ne = new TH1F("ne", "Num electrons",80,0,20); TTree *fChain; //!pointer to the analyzed TTree or TChain Int_t fCurrent; //!current Tree number in a TChain Int_t NELE; //define the type of NELE (the name of a leave in the tree) ne->Fill(NELE); //fill data from a tree to a histogram ne->Write(); //write the histogram into the empty root file created } However, the above commands give me the wrong histogram with only one entry (supposed to be 1000 entries) when I open the histogram with TBrowser. So is there any suggestion? Thnaks in advance! tcli
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