Exactly! Except that I don't do exactly the same things once I met a histogram... oops, a girl... 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
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