Hi,
I am a TCanvas saved to a root file (see attachment). On the canvas, there are couples of TGraphErrors objects. I want to get those graphs using:
sum_spec->GetPrimitive("gTally14");
It returns a null pointer. I try to dump the graph info (see below). It looks a normal graph. I am curious why I cannot get the graph?
Thanks,
Zhiyi.
sum_spec.root (28.6 KB)
{
TFile *f = TFile::Open("sum_spec.root");
f->ls();
TCanvas *c; f->GetObject("sum_spec", c);
c->ls();
TMultiGraph *mg = ((TMultiGraph *)(c->FindObject("mg")));
mg->GetListOfGraphs()->ls();
TGraphErrors *g =
((TGraphErrors *)(mg->GetListOfGraphs()->FindObject("gTally14")));
TCanvas *c_gTally14 = new TCanvas("c_gTally14", "c_gTally14");
g->Draw("ALP");
}
Yeah, thanks.
I realized that the graphs are put together to a TMultiGraph and the MG is plotted on the canvas.