[ROOT] TTree::Draw

From: Woon-Seng Choong (wschoong@lbl.gov)
Date: Wed Feb 11 2004 - 00:17:36 MET 

I have an ntuple which contain variables var1, var2 and var3.
Now, the selection
    ntuple->Draw("var1>>hist(256,-0.5,255.5)", "var2==0)
gives zero entries.  The question is why it draws nothing instead of an 
empty histogram. In addition
     (TH1F *)gPad->GetPrimitive("hist")
gives a zero pointer.  I know why it gives a zero pointer because the 
pad is empty.  But it would be reasonable to get a pointer to a 
histogram with zero entries.


	Thank you
	Seng

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