Change TH2F y axis label


I want to change the labels of a TH2F’s y axis.
I attempt to do it this way:

c = ROOT.TCanvas()

f_in = ROOT.TFile("training.root","read")
CorrelationMatrixB = f_in.Get("Correlations/CorrelationMatrixB")
y = CorrelationMatrixB.GetYaxis()

CorrelationMatrixB.Draw("COLZ TEXT")

But the result remains unchanged. I am, however, able to perform similar operations on the x axis.

Could you please let me know why this doesnt work with the y axis and how to change the labels?

Thank you in advance,

I guess your Y label are alphanumeric labels ? ChangeLabel does not work on them.

The Y and X labels are the same, and this worked on the X axis. So maybe thats not the problem?

Ah ok. so I am wrong. Can you post the root file ? I will look at it.

CorrelationMatrixB.root (5.5 KB)

I uploaded a root file with just the TH2F. Many thanks for taking a look at it.

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With the following example I see what you described (ok on X but not on Y). I need to debug.

   auto f_in = new TFile("CorrelationMatrixB.root");
   TH2F*  CorrelationMatrixB = (TH2F*)f_in->Get("CorrelationMatrixB");
   TAxis *y = CorrelationMatrixB->GetYaxis();
   TAxis *x = CorrelationMatrixB->GetXaxis();

   CorrelationMatrixB->Draw("COLZ TEXT");

Okay, thank you.

Try with SetBinLabel(14,"m(h")) instead of ChangeLabel.


this works!

I made a pull request to fix the ChangeLabel issue. It should work also.

Thanks to have seen it.

Thank you!

This PR is now merged.

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