Cheers
Damir
Rene Brun wrote:
>
> Hi Damir,
> If I understand correctly your question, you want to do something like
> "You are going downtown, looking for a nice girl.
> You do not know her name
> You do not know where she is
> The only thing you can do is to be meet with the first nice girl !"
>
> Translated in Root format, this gives:
> "you have a directory containing objects, including histograms 1-d,
> 2-d, etc
> "you want to get say the first object deriving from TH1"
>
> If the answer is yes, you can use the following loop:
>
> TIter next(gDirectory->GetList());
> TObject *obj;
> while ((obj = next())) {
> if (obj->InheritsFrom("TH1")) {
> return obj; // have found an histogram, return the pointer
> }
> }
>
> Rene Brun
>
> Damir Buskulic wrote:
> >
> > Hi all,
> >
> > Probably a stupid question that has been answered many times but I can't
> > seem to find it in roottalk
> >
> > Suppose I have an histogram in a pad, without knowing it's name or
> > having a pointer to it. How can I get a pointer to it ? I tried various
> > things such as :
> >
> > * gPad->GetListOfPrimitives()->FindObject(...) need the name or a
> > pointer to the object, I don't have it
> > * loop on the list of primitives and try to compare with the
> > obj.Class()->Compare(known_histo) but all objects are put in the list as
> > TObjects, so one doesn't know if they are TH1F's or not...
> >
> > All in all, one always needs the name or pointer to the histo. Looping
> > on the list of histograms found in gDirectory is not very handy,
> > especially if one has histograms outside a directory.
> > Well, it should be simple...
> >
> > Cheers
> >
> > Damir
> >
> > --
> > =====================================================================
> > | Damir Buskulic | Universite de Savoie/LAPP |
> > | | Chemin de Bellevue, B.P. 110 |
> > | Tel : +33 (0)450091600 | F-74941 Annecy-le-Vieux Cedex |
> > | e-mail: buskulic@lapp.in2p3.fr | FRANCE |
> > =====================================================================
> > mailto:buskulic@lapp.in2p3.fr
-- ===================================================================== | Damir Buskulic | Universite de Savoie/LAPP | | | Chemin de Bellevue, B.P. 110 | | Tel : +33 (0)450091600 | F-74941 Annecy-le-Vieux Cedex | | e-mail: buskulic@lapp.in2p3.fr | FRANCE | ===================================================================== mailto:buskulic@lapp.in2p3.fr