Hi,

i have a TGraph and i would like to have some string labels on the x axis, so something like:

Double_t xvalues[3]={“selection1”, “selection2”, “selection3”};

how can i obtain this? I’ve tried the straightforward code above but it does not work…

Thanks a lot

couet
2
I found an example doing that in my macro collection:

```
{
TCanvas *c1 = new TCanvas("c1", "c1",15,49,1051,500);
Int_t numchains=3;
Double_t chain[numchains];
Double_t chainerr[numchains];
for (Int_t i=0;i<numchains;i++){
chain[i]=i;
chainerr[i]=0.5;
};
Double_t time[numchains] = {
0.32528,
2.48328,
0.3505
};
Double_t l2timerms[numchains] = {
0.305687,
12.0619,
0.189249
};
std::string names[numchains] = {
"sequence_L2_muon_standalone_mu6l",
"sequence_L2_mu6l",
"sequence_L2_te650"
};
TGraphErrors *l2timevschain = new TGraphErrors(numchains,chain,time,chainerr,l2timerms);
TAxis *ax = l2timevschain->GetHistogram()->GetXaxis();
Double_t x1 = ax->GetBinLowEdge(1);
Double_t x2 = ax->GetBinUpEdge(ax->GetNbins());
l2timevschain->GetHistogram()->GetXaxis()->Set(3,x1,x2);
for(Int_t k=0;k<numchains;k++){
l2timevschain->GetHistogram()->GetXaxis()->SetBinLabel(k+1,names[k].c_str());
}
l2timevschain->SetMarkerStyle(21);
l2timevschain->Draw("AP");
}
```