RE: [ROOT] TTree.Draw(), strings-problem

From: Philippe Canal (pcanal@fnal.gov)
Date: Thu Jun 10 2004 - 17:53:54 MEST


Hi,

You should use:
   myTree.Draw("pullforce>>h_type031251_fm7(30,0,0)", "type==\"031251_\" && fm==7") 

Cheers,
Philippe.

-----Original Message-----
From: owner-roottalk@pcroot.cern.ch
[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of Bernd Reinhold
Sent: Thursday, June 10, 2004 7:47 AM
To: roottalk@pcroot.cern.ch
Subject: [ROOT] TTree.Draw(), strings-problem


Hi!

Root gives me the *ERROR 30 : Bad numerical expression: "031251_"
and the corresponding line in the code is: myTree.Draw("pullforce>>h_type031251_fm7(30,0,0)", "type==031251_ && fm==7") 
type is a Branch of type char*. The second error-message is:
Error in <TTreeFormula::Compile>: Both operands of the operator == have to be either numbers or strings
I tried to put the string in tickmarks, but received a similar error-message: "type=='0210708' && fm==7" but then it complained:
ERROR 30 : Bad numerical expression: "'0210708'"
Error in <TTreeFormula::Compile>: Both operands of the operator == have to be either numbers or strings

Is there a way to enclose the c-string (with something else than tickmarks), such that '_' is recognized as part of the string?
(I'm using 3.10/02 of 1 april 2004 on a CERN-RedHat)

Thank you, 
Bernd.



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