Drawing vars from a TTree

From: Nick van Eijndhoven (Nick@fys.ruu.nl)
Date: Thu Jun 26 1997 - 10:08:42 MEST 

Dear ROOTers,
I have all my physics column wise ntuples now converted into root
files (i.e. trees) and would like to do the following :

* Draw variable A versus B with a weight W under the condition that C>D

In PAW I can do this by :

nt/plot 999.A%B W*(C.gt.D)

and in ROOT I tried :

Root> TChain q("h999")
Root> q.Add("test.root")
Root> q.Draw("A:B","W*(C>D)")

but when I inspected the produced 2-dim histo in Lego layout all
heights were at 0.

Question : How to achieve this in ROOT ?

                                                  Thanks,
                                                   Nick.
*----------------------------------------------------------------------*
 Dr. Nick van Eijndhoven                Department of Subatomic Physics
 email : nick@fys.ruu.nl                Utrecht University / NIKHEF
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 WWW : http://www.fys.ruu.nl/~nick      Office : Ornstein lab. 172
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