Axis ticks with alphanumeric bin labels and variable bin size

[fsili]

Hello everyone.

I’m sorry I have to ask this, as it may be a very simple question.

I have a histogram h1, for example, with variable bin size with low edges

(8,15,20,25,30,40,50)

with the last bin in the range 40-50. I want to plot this histogram but with bin labels, each of them indicating the bin range. For example, in bin with range 40-50, I want a label between the ticks that reads 40-50.
I can manage to do that, but the problem is that the ticks don’t appear at the low edges of the bins, instead, I get them each 10 GeV. Here in the image I set bin labels to be “bin”, but that’s not the problem

Here is the simple code I used to plot this histogram

double lowedges[7] = {8,15,20,25,30,40,50};
TH1F * h1 = new TH1F("", "", 6, lowedges);
// Fill Histogram
for (int i = 1; i<= h1->GetNbinsX(); i++)
{
      h1 -> SetBinContent(i, 1+i);
}
// Change bin labels
for (int i = 1; i<= h1->GetNbinsX(); i++)
{
      h1 -> GetXaxis() -> SetBinLabel(i, "bin");
}
h1 -> Draw("hist");

So, how can I modify the ticks position to be at the edges of the bins?

Any help is very appreciated!

Thank you very much,
Francisco

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[oshadura]

@couet can you take a look, please? Thank you in advance!

[couet]

@fsili

So, how can I modify the ticks position to be at the edges of the bins?

You will need to make the tick size equal to 0 to make them disappear and redraw ticks using TLIne at the positions you wish. There is no automatic way to do it. But a generic macro can be written.

[fsili]

Oh, somehow I expected it .
Thank you very much for your answer!
Cheers,
Francisco

[couet]

But, as I said a macro, can do it.
Try this one:
graphtext3.C (1.1 KB)

[fsili]

Oh!! Thank you!! Definitely gonna use it!

Thank you!
Francisco

[couet]

Of course it has to be adapted to histogram. But the idea is the same.
Note also that when you move a point interactively the table and tick follow.

[fsili]

Yes of course! Sure I am going to implement it! Thank you, again, very much!