How to set Y axis in hstack?

Hi,
I tried

yAxis = hstack.GetYaxis()
yAxis.SetTitleOffset(1)

but it shows :

Traceback (most recent call last):
  File "plot3.py", line 86, in <module>
    yAxis.SetTitleOffset(1)
ReferenceError: attempt to access a null-pointer

And it works with:

yAxis = h1.GetYaxis()
yAxis.SetTitleOffset(1)

The only difference is h1 is a TH1F, and hstack is

hstack = ROOT.THStack()
hstack.Add(h1)
hstack.Add(h2)

Jen

Draw the stack before trying to get its axis.

And add gPad->Update(); gPad->Modified(); after having drawn the stack. This will force the axis creation. Axis are created at drawing time only.

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.