Hi Malcom,
If your branch contains strings (declared as name/C), then you can use
the C function strstr in your cut. Example
T->Draw(""rms","strstr(field,\"field_cut\")")
More operators could be introduced to support the search functions
in TString or C++ string.
Rene Brun
Malcolm Davidson wrote:
>
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>
> Hi Rene,
>
> Thanks for your reply but I'm afraid I didn't express the root of the problem clearly.
>
> What I actually wanted to ask is whether a cut could be made with the draw command
>
> using a branch containing strings. As an example:
>
> I have a tree T containing two branches one labelled "rms" and contaning floats and the other
>
> labeled "field" and containing strings, then it would be nice to be able to plot a histogram of
>
> all values having field == "Field1" with the commands
>
> TString field_cut = "Field1"
>
> T->Draw("rms","field == field_cut");
>
> Even better of course would be the ability to use REGEXPs :) but I would be happy if the first
>
> case was already implemented.
>
> Kind regards
>
> Malcolm
>
> >Hi Malcom,
> >There are two TTree::Draw functions:
>
> >Draw(const char* varexp, TCut selection, Option_t* option, ...
> > Draw(const char* varexp, const char* selection, Option_t* option,...)
>
> >What you request with TString is implemented with TCut.
>
> >Rene Brun
>
> Malcolm Davidson wrote:
> >
> > Hello,
> >
> > I was wondering if the selection based on TStrings for the TTree->Draw()
> > command had been implemented yet (based on my attempts not) or whether
> > this useful feature (here I'm quoting from a 1999 email from Rene Brun)
> > will soon be added ?
> >
> > Many thanks in advance
> >
> > Malcolm
> > <>------------------------------------------------<>
> > Malcolm W. J. Davidson
> >
> > Centre D'Etudes Spatiales de la Biosphere (CESBIO)
> > UMR 5639 CNES-CNRS-UPS
> > 18, Avenue Edouard Belin
> > F-31401 Toulouse Cedex 4
> > FRANCE
> >
> > e-mail : davidson@cesbio.cnes.fr
> > phone (33)(0)5.61.55.85.84
> > fax (33)(0)5.61.55.85.00
> > <>------------------------------------------------<>
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