Histogram with "/" in name


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ROOT Version: 6.24.02 (pyROOT)
Platform: Linux WSL1
Compiler: Not Provided


Good morning ROOT experts,

I want to ask regarding a possible bug
that I am facing, when trying to ‘Get’ a histogram whose name includes “/”
but is not in any directory.

I re-produce this behaviour if I do the following:

file = ROOT.TFile.Open("test.root","RECREATE")
hist = ROOT.TH1F( '/a/test', '', 100, -4, 4 )
hist.Write()
file.Close()

file = ROOT.TFile.Open("test.root","READ")
file.Get('/a/test/')

returns: <cppyy.gbl.TH1F object at 0x(nil)>

This appears to be a null-pointer.
The histogram is clearly visible and functioning in the TBrowser,
however I cannot seem to be able to escape the “/” character to ‘.Get’
it from the file. Perhaps ROOT is trying to find directories with that structure
and fails to find them thus returning a null-pointer?

Please excuse this post if this is mentioned as a no-go somewhere in the documentation.
Thank you very much in advance,
Ioannis

May be this FAQ can help you.

Thank you, this fixes the issue!